Reefing The Australian Way Forums

Absolutly awesome.
The best aquascaping i have seen yet IMO.
Am going to use these ideas in my tank build which is happening now.

Very wel done mate, its a tribute to your hobby.

kell wrote:Hey Ollie. Was just looking through your photos. We need an update

is she still running mate? i hope so. you must be away for work alot i'm guessing?

Probably time for an update.

Well how hasn't time flown by? I'll have to try to list the changes over that time.

2012 - By about April you couldn't even see in the tank anymore. I was due to be married in October and there was less and less time devoted to anything else. I think macro algae started getting out of control in the DT further suppressing any motivation for the tank. It stayed in this sorry state for a while.

2013 - Started new job, only drawback was it was based in Perth. Ultimately my commute was getting home for a couple of nights once a month. There's no denying 2013 was pretty shite (even moreso than this year if you believe). The tank was just ticking over with the wife (whom stayed in Wollongong the whole time) taking care of feeding and top-up water.

2014 - Early in the year wifey visited me in Perth for a weekend. I remember when she called telling me she'd got home and all the fish died. The main pump failed. With 750W of halides it would have only been a matter of time; the chiller is dependant on the main pump to get the chilled water to the DT. Many of the corals were hit hard too. Better news in March, we were expecting our first baby. This triggered some decisions such as committing to a permanent Perth move necessitating the closure of the tank. Short lived though as my employer closed the Perth base - I was relocating to Sydney by Feb 2015. The few remaining corals and clams ticked over until...

2016 - Bought a house in Sydney and had to move after selling our place in Wollongong. Tank had to go and everything packed into boxes. The stand was squeezed through the door into my workshop room and the tank in the garage on moving dollies.

The good news is that the stand has moved into position. This basically required me to pull it apart despite getting it into the workshop in one piece (sans the decorative trim) although I did need to remove the door from the garage to the workshop and persuade it through the opening with a sledge hammer.

The sad news is that I'm probably updating to an empty house.

Wow, similar thing happened to me too, sold it all in readiness to build our new house, congrats on the wedding and moving

Hey Ollie,
Good to hear from you. Tank crash while you're away is the worst. Glad that it hasn't beaten you are you're ready to saddle up again.

The sad news is that I'm probably updating to an empty house.

That might be the case, but the good news is that you chose to visit on a day that the board is actually working. Has been down for a couple of months, and only came back up in the last week or 2.

Daz the reefo wrote:Wow, similar thing happened to me too, sold it all in readiness to build our new house, congrats on the wedding and moving

Hi Daz I take it you managed to build the house? Was that at your place when you had the tank or did you end up moving? Any plans to get your toes wet again?

Basenji wrote:Hey Ollie,
Good to hear from you. Tank crash while you're away is the worst. Glad that it hasn't beaten you are you're ready to saddle up again.

The sad news is that I'm probably updating to an empty house.

That might be the case, but the good news is that you chose to visit on a day that the board is actually working. Has been down for a couple of months, and only came back up in the last week or 2.

At least it's still here I suppose. I half expected to get a 404. I re-read my TJ to help remember what I did. I also reviewed the many pics I took. Primarily I was looking to remember how I had constructed the stand. I knew that I built it so that I could be taken apart but I had forgotten the detail. I also recalled that liquid nails was involved but as it turned out the adhesive let go of the 3mm ply quite easily and without mess. I was pretty sad to lose those fish compounded by being 4000km away from the tank at the time.

What I do remember is how much power this thing consumes. Given my current circumstances where I've been stood down for the past 6 months and which is looking to go on a fair bit longer too I approach this with some trepidation even with the 5KW solar array on the roof. Then again it might take me another six months to get it wet. Everything these days just seems to take ages to do - I blame the kids . That's on top of the usual 5min job taking 3 hours.

So I've disassembled the stand and reassembled it in its new location. Originally a peninsular the tank's new location only lends itself to a more traditional placement. I do still have the end accessible to viewing.

FTS of sorts:


Even though the inside of the tank stand was painted with oil based paint, the salt spray got under it. The timber is still pretty good but it would have just been a matter of time before it really deteriorated. I had a product on hand to seal out water at a molecular lever or so it touts - Shower Plug. I applied it to the two middle legs and a bit around the bottom of the formply. With the inevitable spills I found that salt water had started to foul the ply veneer at the bottom. I did originally silicone around the inside perimeter. I didn't expect it to but the silicone held all the way around without lifting anywhere so I'll reapply this treatment too.









I've also picked up some new black signwriter's vinyl to apply to the "back" of the tank.

In the meantime I set up the sump on the garage floor and tipped a 2 litre container of vinegar in with water to circulate for a bit and loosen the old build up which never got cleaned when the tank was shut down. It was a bit weak given about 120L of water is required to get to a minimum level. I also made a couple of changed. I'll post those another time. Should be in bed.

After some robust discussion with the wife there's been a change of plans. Very nearly abandoned the idea of setting the tank up again but happy wife, happy life right?

I've been convinced to take to the kitchen with a saw. This will position the tank as a peninsular set-up again. So didn't need to get the signwriter's vinyl





The sump has been cleaned and ready to go.

The silicone I placed around the base of the stand appeared to have worked well. I expected it to not hold on the form ply but it did and has now been re-applied this time to the entire inside of the stand rather than just around where the sump was placed.

I took the covers off the chiller to find a bit of rust. Gave it a bit of a rub down and then sprayed the base with lanolin.







I mentioned a couple of changes to the sump. Originally I had five holes from a Calfo style over-flow from the Macro Algae chamber. This resulted in noise and bubbles into the return chamber. I took to it with the angle grinder. The Calfo weir had to be removed and I'll probably replace it with an eggcrate fence as the noise and bubbles are significantly reduced without it. The micro bubble problem is still yet to be resolved but I may get away with it by moving the return pump to the front chamber. I'll have to wait until all the plumbing to the tank is in place though.



The second change is to the return chamber where I've drilled another hole. I don't know why I hadn't done this before. It is an easy redundancy to build in. The last change was to the entry chamber on the left where I've cut a small escape into the chamber before the macro. The entry chamber runs about 95% full. The cut I've made won't take the full flow but will absorb short term increase in flow or partial blockage of the exit to either the DSB (left) or drain (32mm bulkhead). The other solution was to increase the size of the bulkhead up to 40mm. This is still on the cards btw.

Where are the microbubbles generated? Is it from the skimmer or from water entering the sump?

As the water goes over the baffle into the return the fall is enough to reintroduce bubbles since it is only a half bubble trap. Problem is that I can't really have the third baffle of the over-under-over unless it is able to vary in height given the changing level of the return. Possibilities as it stands is a third baffle made of some coarse matting or relocate the pump to the front part of the return. Although I don't recall there being an issue with bubbles into the display when it was running before so it may just be a perceived problem. All the bubbles on the journey from the display to the sump and the skimmer should be captured by that last section. The macro in that chamber just before the return catches anything remaining only to make new ones just before the return.

I'd been looking to find replacement crushed marble for the DSB. Called a few places in Sydney but the closest I got was marble dust. I came across White Rock Industries in Raglan(Bathurst) which stock white crushed marble in multiple sizes including #00 and smaller but wasn't about to make a special trip. I did however find myself camping with the boys in the Hampton State Forest (Jenolan/Oberon area) this week, conveniently located just under an hour from Raglan. Picked up a 25kg bag of #00 as well as 25kg of .6-.8mm. Still yet to lift the tank onto the stand though.



Unpacked some of the old equipment too. Gee I spent some dollars on rust and disappointment. I'll make some long term review posts soon.

The problem I found with white crushed marble, any build up or little pebble gets into the magnetic cleaner and it scratched my glass so bad..

pilonstar wrote:The problem I found with white crushed marble, any build up or little pebble gets into the magnetic cleaner and it scratched my glass so bad..

I'm paranoid about any type of substrate getting under the glass cleaner. I have the Hammerhead with the blade extension - need to be careful not to drive the Hammerhead along the blade otherwise there is a risk of scratching. The crushed marble is for the DSB anyway. I prefer aragonite sand for the display and only as thin as it needs to be.

I've set up the QT again. I'm running it with an old Resun CL450 chiller. This has been a good little unit although I have had to change out the fan bearings and I made the mod to extend the temp sensor. Anyway I hooked it up and it still worked just fine. Some time ago I lost the LCD digit after the decimal point but since the changes are 0.5*C at a time the missing digit is manageable. It was all in place before I then found it was leaking internally. After opening it up I found luckily that the leak was only from a loose gland and suitably fixed by nipping it a bit tighter. Anything more than that is considerably more difficult to fix because of the refrigerant lines.





QT in situ.

I've been slowly plugging away at getting things done to the setup. Still haven't lifted the tank onto the stand yet though so doing what I can in the meantime which is much.

I started by getting the old liverock out of storage figuring that it would need to be soaked for some time to get the PO4 out. Firstly the dead material needed to be removed and I started by scrubbing with a toothbrush and nailbrush. This got old real quick and I loaded the pressure cleaner and blasted away. I can't remember how much rock I got, I think it is in the order of 100kg. Some before and after pics.









The rock is now sitting across 4 tubs filled with RODI water. I've been testing with the Hanna LR PO4 checker and the highest was 0.17ppm. I was expecting higher after a few days TBH but there is also the consideration that the test reagents expired in 2013! It does test 0 with new water though so I'm confident that the PO4 is leaching out of the rock, also given that the water has a distinct yellow tinge after a few days too. I added a jar with a bit of LaCl (LoClor pool starver brand) in each of the tubs. There is a crust forming after a few days so it gets a stir every so often and using the Lanth I don't need to be changing out the water anywhere near as often.

Progress!

The tank got lifted into position last week I hired aN hydraulic scissor lift table. It was a bit of a mission to get it because despite numerous hire locations across the city the scissor lift table is hired ex their lift and shift branches of which there was one out at Ingleburn - an hour’s drive away.

The lift itself went surprisingly easy. As part of the preparations for the lift I calculated the weight of the tank itself being 130kg. I knew I could lift one side of the tank up a bit which allowed wifey to pack beneath it with styrofoam. Repeated until I could wheel the table under it to make the lift. It was then slid over onto the stand, job done.







Bulkheads back in.



Wet

Exciting to see a new tank being filled.
Well done on getting it into position.
Will be interesting to see the aquascape that you build around the closed loop returns. They present challenges, but are worth the effort.

I have 2 CL returns in the base of my 3x2 tank. I initially planned to have eductors on them. They ended up not giving a huge advantage, and were hard to obstruct with the rockwork. I ended up ditching them, and just have straight PVC pipe outlets.

Just as a word of warning, I also recommend making sure you are thoroughly confident it the bulkheads and plumbing to the returns, as once the tank is full of water there is not much you can do to work on them without emptying the tank. Back in 2018 I had one of the barbed fittings crack on the closed loop returns on the base of the tank. I managed to drain about 180L into buckets and drums to get water level below the fittings on the bottom of the tank. Scrambled to repair plumbing (actually had a spare fitting, thank God) and refilled the tank. Lost about 60L that seeped through the floor boards.

Yeah the bulkheads will always be a point of doubt. They haven't leaked so far and water has been in it for about three weeks now. I had a close inspection of the seals, which were thoroughly cleaned and checked, once installed. The two sealing ribs are concentric and free of debris on all of the bulkheads. There are still six points of failure(and another three in the weir) which as you've mentioned will be a right PITA to attend to should any of them fail - 700L sitting above them.

If I had my time again I don't think I'd go for holes in the bottom of the tank. Propeller pumps have progressed and the need for the closed loop has passed IMO. Here is my Reeflo Dart:






And the Oceans Motions:




OM is gone I think. That was the replacement motor, which I could only get in 110V too at great cost. Unless I can find something local I think it will be relegated to the priciest 5-way PVC plumbing to be found. Still undecided whether I replace the Dart. Maybe I can get the motor bearing kit and a new impeller but even the housing is in quite a sad state. I did have the thought to use one of the five CL returns and plumb it via the chiller. This would satisfy the desire for a redundancy to the main pump which was the reason for the tank crash. The con is that the CL would need to be run continuously whereas before I ran it in conjunction with lights-on plus a bit.

As for the eductors, well I think the claims were overstated but I've put them on again for now moreso for the ability to aim them but with the pump in pieces I've had to guess.

The rock was in tubs with LaCl for over a month and they got a few water changes in there too. I've put the rock in the display. Initially I was just going to throw it in and aquascape later but I found myself positioning them. Actually I thought I would be aquascaping dry and using cable ties and aquakneedit but it didn't happen and all the rock is stable but untethered, for now anyway. I did take pics but they are so badly affected by reflections they don't really show anything. I did get one from the end. The aquascaping ended up much like it was. In essence there are two bommies linked by a bridge. I think I did a good job of hiding the CL eductors and remebered to try to keep the height of the rock down. I don't think I went over three-rocks high and tried to keep more of the floor exposed which will eventually get sand, ie arognite or crushed marble.


The skimmer has been performing very well especially given it's supposed to be a near sterile tank ATM. This from under 24 hrs:


It is on the wet side but the skimmer keeps pulling this out. Although I used NSW at 1.027 I was about 150L short which is basically the sump running capacity. I reclaimed about 60L putting the rock in but SG sits at 1.021 for now. I'll get a bit more back when the S of the DSB is added again. Should see better skimmate again when the SG rises to normal.

You'll also see a temporary (semi-permanent perhaps) solution to reduce the spray in the cabinet - the styrene lid. Years and the thought never crossed my mind.

I have noticed that the water has yellowed. This is coming from the rock because I noticed the tub water was getting quite yellow but looked pretty clear towards the end of the time in the tubs after the last water change. I'll probably use carbon to try to clear it up. In my single days I think I'd just drop the airstone in and pump ozone with a window open but probably best not to do so with the kiddies and wifey hanging around all the time.

Tested the PO4 on the Hanna. After the tank was filled it was 0.02ppm. Yesterday it came in at 0.12ppm. I'll be sitting a jar of LaCl in the sump soon and see how that goes.

basenji wrote:Back in 2018 I had one of the barbed fittings crack on the closed loop returns on the base of the tank. I managed to drain about 180L into buckets and drums to get water level below the fittings on the bottom of the tank. Scrambled to repair plumbing (actually had a spare fitting, thank God) and refilled the tank. Lost about 60L that seeped through the floor boards.

You mention barbed fittings, how did it crack? I assume the barb is on the sump side but obviously the seal was compromised. Did the plastic deteriorate over time do you think? I'm using Hansen bulkheads with the threaded tail. They still seem good with some flexibility. I have noticed the plastic of the Loc-line I was using to direct the return all cracked, just about every segment failed. The Andries faux locline on the eductors still seem ok as do the eductors themselves but, although immersed, they have been shadowed by the rock.

Did some work on getting the chiller into place. Previously it sat outside the cabinet. It is a Hailea 1000. The chiller part ie the compressor is ok for noise but it has a large fan internally and it is bloody noisy. Well the fan is quiet but the noise is from the large volume of air it pushes. My plans were to always have it in the cabinet and I prioritised all the powerboards and ballasts so that the chiller wouldn't fit. This time I'm trying to keep as much of the electrical connections outside the cabinet so the chiller is in.



I lined the outer walls with noise attenuating foam tiles. Unfortunately even though when doors are closed most of the noise is suppressed, the vibrations of the running chiller resonate with the stand so there is a deep hum. Will need to try some noise mat under the chiller.


My plans are to use the closed loop and plumb the chiller as part of it using the outlet pictured here. For the time being the chiller return is routed via the spiral hose round the outside and though the hood direct into the tank.


This is a 240VAC fan originally from my first tank running a single 400W halide. The fan ran air through the light fitting, for now I've tried hooking it up to a Jaycar temp controller and directed the exhaust over the DSB section of the sump to try to get a bit of evaporative cooling too. So far it's a fail. It doesn't move enough air but I had to try. I think I'll have to cut into the stand on the opposite side to the doors, something I've managed to avoid. There is a significant amount of strengthening added to the stand from the sheet of 3mm ply which will be lessened by cutting into it. However, given the difficulties accessing the side of the sump away from the doors and the need for more air out the back of the chiller I think I have resigned myself to the fact I need to cut holes in that sheet. I just have to remind myself that the stand is still very sturdy with the skeleton of 90x45mm pine, tripled in the corners and pinned by many 120mm 10G SS bugles and I'm not removing the sheet either.


This barbed fitting is causing grief. It won't stop leaking. I tried filing the production mould line smooth as well as using teflon tape and two hose clamps but it still leaks. It will be getting silicone sealant soon. The other barb - no issues Actually the problem is probably more with the spiral tube so my last option will be to use a short piece of PVC to connect to the barb and a hose joiner to the spiral hose.


I reused a crossflow fan to get air into the front of the chiller. Cutting into the base to access cool air from there.


It just sits there and is easily accessed if needed.


Overall the chiller install is still a work in progress as initial testing has hit problems with heat dissipation.

Cleaned the Lumenbright reflectors for the first time ever. I was quite worried that the salt splash may have eaten into the polished metal. I used a metal polish compound and elbow grease to try to clean them up. As expected I actually put some micro scratches into the reflector by way of loosened muck contaminating the polishing cloth. Overall the reflectors cleaned up reasonably well however even though it didn't look like the metal was eaten into the salt splashes have left many stubborn marks. I'm thinking that I'll be moving to LED at some point and have started to investigate what's available in the market now. Just on bulbs alone if you were to pick a say $4K budget with bulbs running at ~$400 x2 pa that's a 5 year break even! I'm yet to give detailed thought/calculations to the power costs not just for the lights but the chiller run time too, but I reckon it'll probably bring the break-even down to 2.5 years.
Before:


I also added the DSB. Didn't bother with rinsing it. #00 on the bottom and 0.5-0.8mm on top. Very little clouding. Most of the fine dust is captured in the DSB itself. What escaped either settled or was skimmed out.




You can see the Two Little Fishies Phosban reactor installed too albeit empty. PO4 is still leaching out slowly. I've been sporadically testing with the Hanna and expired-in-2013 reagents. PO4 got up to 0.18 when I then added a jar of LaCl into the calm front return. Hence the need for a little bit of flow so I installed the Phosban reactor to test its ability to not leak and use the outlet to turnover the front return chamber. After about 5 days I tested again to read 0.08. Winner on the Lanthunum Chloride. That jar is 150ml worth of shaken Starver product allowed to settle and then decanted into that jar and allowed to settle again before going into the sump.


I found a bucket of aragonite - size #00 or so I thought. As I gave it a rinse and added it to the display I realised that it was a mix of #00 as well as oolite. Then I remembered that this was the sand from my first tank's DSB. All Caribsea aragonite. The sizes were well mixed now. It looks good in the tank but I expect it will leach a bit more phos too.

Looking good

CheezotheClown wrote:

pilonstar wrote:The problem I found with white crushed marble, any build up or little pebble gets into the magnetic cleaner and it scratched my glass so bad..

I'm paranoid about any type of substrate getting under the glass cleaner. I have the Hammerhead with the blade extension - need to be careful not to drive the Hammerhead along the blade otherwise there is a risk of scratching. The crushed marble is for the DSB anyway. I prefer aragonite sand for the display and only as thin as it needs to be.

Have a look at the new Tunze Scrapers. I run 00 sand and you would actually have to try to pick it up with the scraper to scratch the glass - they are that good. Tunze also (fairly) recently bought out little foam bits you can clip on to make it float if it does become disconnected (and on the outside it makes the magnet more comfortable to use)

Thanks Macca. I'll keep the recommendation in mind. I've got the Hammerhead and just ordered a new wet side because I noticed my original had bubbled from rust pushing the pad out a bit. I think the Tunze gear is pretty good but I'm struggling with the brand after two of four 6105 pump motor blocks have failed, three of four power packs, and now the moonlight on the 7096 controller flickers It is ten years old but has only been used for about three.

I've got 4 x 6105's (for over 10 yrs). 1 motor block has failed and 2 power supplies. Happy with that (I'm actually cutting the ends of the power supplies now and just running them from 1 bigger 24v adaptor (used to run POS machines - rated at 220W). 2 x Tunze are running 60W max so the power supply isn't even anywhere near capacity - especially when you consider the ramping up and down they rarely run at 100% simultaneously).

I've also got the Hammer head and won't ever use it again - the Tunze scraper is miles ahead

I think I'll be making a mod to a single power supply too. You're running 24V? I thought the 6105 was 18V, at least the pre 2015 model, the new motors are up to 24V (I think).

CheezotheClown wrote:I think I'll be making a mod to a single power supply too. You're running 24V? I thought the 6105 was 18V, at least the pre 2015 model, the new motors are up to 24V (I think).

I read somewhere they can go to 30v, but the jumpers that come standard with the power packs are 12v, 18v and 24v (so I settled for 24v).

The powerpack I am using is this one (I had a few lying around)

https://www.ebay.com.au/itm/UMEC-UP2002 ... ctupt=true

rated to 200W

The reason I am moving to this is I will eventually move them to run from 12v batteries via a step up convertor like https://www.ebay.com.au/itm/WaterProof- ... fresh=true and keep the batteries charged. This way in a power outage the pumps don't miss a beat

Macca_75 wrote:

CheezotheClown wrote:I think I'll be making a mod to a single power supply too. You're running 24V? I thought the 6105 was 18V, at least the pre 2015 model, the new motors are up to 24V (I think).

I read somewhere they can go to 30v, but the jumpers that come standard with the power packs are 12v, 18v and 24v (so I settled for 24v).

The powerpack I am using is this one (I had a few lying around)

https://www.ebay.com.au/itm/UMEC-UP2002 ... ctupt=true

rated to 200W

The reason I am moving to this is I will eventually move them to run from 12v batteries via a step up convertor like https://www.ebay.com.au/itm/WaterProof- ... fresh=true and keep the batteries charged. This way in a power outage the pumps don't miss a beat

That 12V transformer is a good option. Quite cost effective when looking for a 24VDC power pack.

I've got two of those step-up regulators on the fourby to run the spotlights. Not sure on their efficiency, nor do I really care on the 4x4, but given the significant passive heat sinks I'm thinking not particularly so; ie heat as a function of energy loss. Then again how pedantic does one need to be? In a power outage you've probably got a few hours before becoming a significant risk. A 12V backup running even four Tunze 6105's would give hours more. By then you'd try to have a gennie online to power your fridge and send charge to the tank for the Tunze's and whatever else to the capacity of the gennie.

I priced a 200AH Enerdrive Lithium to replace the two 105AH AGM's in the camper (which would then go to the tank backup system). $3K! Not yet I think. Still have to earn back the losses for 2020 and still yet to see if I'll still have my job later in the year. These State clowns have directly cost me thousands in lost earnings and millions to my industry and millions more to the support industries.

I digress though.

When I set up the tank again I was determined to hold water in reserve. Previously I had a total of 9x 25L drums so the best was ever to be 225L. I did however live 5 minutes from the Bellambi boat ramp down in Wollongong but aligning days off, tides, weather and motivation could easily see weeks before a chance to collect more NSW.

Now I've picked up 16x 20L (23L stamped on drum) in addition to the 9x 25L. I've also got a box trailer to cart it all and I picked up a couple of 200L drums. One was actually a rain water drum from my old house in the Gong which I never got around to using and the other was used for Hydrochloric acid, so perfectly sterile. The 16 smaller ones had cola mix. It turns out that they were much harder to clean than anticipated. The cola smell was still evident after lots of water, acid wash, bicarb wash, more water. After filling with NSW the cola smell would taint the water after a day or so. It's getting better but probably wouldn't do the cola drums again.

The new 200L drum needed to have a bulkhead installed. The trouble was that the lid was sealed closed. Access hole cut with the largest hole saw I had, bulkhead installed, and the hole welded back into place reusing the plastic shavings. I love the gas soldering iron I have. Very versatile and came with the plastic soldering tip.







The trick was how to hold the "hole" in place while gravity was trying to take it to the bottom of the drum, hence the bolt which had a piece of string tied to the inside so it could be pulled out after removing the retaining nut on the outside.

I can use a pump or if the drums are about half full, gravity to fill the tank (via the sump). I use the same hose and pump as used to collect the water. The system is also expandable so another drum or two can easily be added.

I made a little styrene lid in addition to the styrene "plug". I could see that rainwater could pool around the plug which would make its way into the drum as the plug really just keeps dust out. The lid should keep all but a bit of spray away from the plug recess.

I run a step up (12v -> 14v) for theTravelbuddy in the car - minimal to no heat loss. I don't think there would be a lot when stepping up 12v -> 24v anyway. I'll be mounting it in a well vented area.

Batteries will be stored under the house, 12v feed up through the wall and then the magic will happen.

For me it's about piece of mind. I am leaving the tank with a sitter for 6 months (with someone checking in every now and again) - I don't expect them to setup Gennies or anything.

Macca_75 wrote:I run a step up (12v -> 14v) for theTravelbuddy in the car - minimal to no heat loss. I don't think there would be a lot when stepping up 12v -> 24v anyway. I'll be mounting it in a well vented area.

Batteries will be stored under the house, 12v feed up through the wall and then the magic will happen.

For me it's about piece of mind. I am leaving the tank with a sitter for 6 months (with someone checking in every now and again) - I don't expect them to setup Gennies or anything.

Yeah, certainly best to keep the tank sitter's job as simple as can be. My considerations for using any step-up/down, transformer/rectifier devices is the power loss. But as you say, not much heat probably equates to minimal losses anyway.