Homemade growing tank's height question

[sevynos]

Hi all,

I'm about to need a new tank for my juvenile ancistrus. As my budget is quite limited and I must also consider total weight of tanks I thought about building my own "non standard" tanks.

So the question is: What is the minimum height a tank should be for them. As these are bottom dwellers, I've guessed that eight inch high of water would be enough for them. Am I right or more height would be required?

Thanks

[plecomanpat]

that would be fine...imo

[sevynos]

Thanks for your opinion plecoman!

Very pleased to have a reply from somebody with your experience with plecos!

I will still way a little for some more opinions but I must start building the tank soon as it's a long process.

[Bas Pels]

The only thing I wonder for an 8 inch = 20 cm high tank is stability. If the tank is in a fishroom, warmed by the other tanks in the room, I'd say 8 inch perfect

But if it is standing on a table, somewhere, I'm afraid the low water level (5 mm sand on the bottom, 2 cm of air above, thus 7 inches of water) might provide large fluctuations in temperature

further, as a 8, 12 of even 16 inch high tank can basically contain the same amount of fry, the higher tank will not build up a similar amount of nitrates, an 8 inch high tank might need much more waterchanges.

But that is a consideration for you, not related with the matter of a 8 inch tank is possible

Personally, I have only tanks 30 cm high or more

[Suckermouth]

I agree with Bas. Not only do you have the temperature issue, but other water quality characteristics are also more variable. Grow-out tanks tend to have a lot of food input (and thus potentially a lot of decomposing food), and a larger tank will dilute the decline of water quality that commonly occurs when you feed heavily for fry.

On the other hand, the cost and weight savings of "shortening" most tank sizes is not huge, either, so I imagine for it to even matter you're thinking of having a short but still a fairly long/wide tank, in which case that would make up for the volume. Is this correct? Because if you want to shorten a 10 or 20 gallon tank you're probably better off just getting the standard one; cost and weight are not going to decreased that much but at those smaller tank sizes greater water volume is better.

Very small fry aren't too affected by being in very shallow water based on my experience with floating breeder traps.

[plecomanpat]

I have 4 breeder tanks, 3 @30 gal and 1 @ 20 gal...all at 10 inches in height and have no problems with any of them...they are in a rack,and do bi-weekly water changes...I use these tanks for the reason of space...more tanks on the rack.IMO water changes and vigilance are your best defense.

[sevynos]

But if it is standing on a table, somewhere, I'm afraid the low water level (5 mm sand on the bottom, 2 cm of air above, thus 7 inches of water) might provide large fluctuations in temperature

I imagine for it to even matter you're thinking of having a short but still a fairly long/wide tank, in which case that would make up for the volume. Is this correct?

I plan on having 6 tanks in this small room. I calculated 8 inch of water with no substrate so the tank will be 9 inch high. It will also be 48 inch long by 20 inch wide. So the capacity will be about 33 gallons.

There will be a central filtration system. The water will be shared between three tanks making something like it was a 100 gallons tank.

Concerning temperature, the heating/cooling will occur in the filter and will be computerized. So even a small change in temperature will trigger some correction action. The only drawback I can think of is water change. These may be more complicated. I will have to think about a good solution!

Now, having these supplemental information, what do you think of the setup?

[Bas Pels]

3 tanks in a system is much more stable than 1 tank.

After all, we all make mistakes, and thus we sometimes overfeed. But do we overfeed 3 tanks in a row? Nope

So I think the new information - and the fact we are talking about fairly large tanks, 48 inches = 120 cm and 20 = 50 cm, that I'd say: do it

I only wonder, did you calculate enough room between the tanks? I got a tank with only 10 cm 4 inches above it, and this is too narrow. Each tank needs 20 cm - 8 inches - of room above it, unless it is a big one, needing more

[plecomanpat]

Agreed...I set mine at 9" apart...enough room to move around and if you want to introduce large pieces of driftwwod...Enjoy

[sevynos]

Thanks mates for your inputs!

Actually I had previously planned 4 inch between tanks. So I will correct my plans to find a way to fit all this in the room considering that the bottom tank must be at a minimum of 2 feet from the ground. That is for the filtration as water will get to it by gravity and must be higher than the filter itself!

The only thing that is still to find, is glass thickness. All the calculators I tried seems not be made for shallow tanks as they give 6mm thick glass. IMO it's quite thick for 8 inch of water! My 77gal tank have 9 or 10mm glass and it's 2 feet high, 4 feet long!

Does any of you know a calculator for shallow tanks?

[Bas Pels]

Can't provide a link, but although I might try 5 mm, I would not go thinnner. Somebody might incidentally hit the taks, for instance

Further, 5 mm is - in Europe - not a thickness one can find, only 4 mm and 6 mm. And I would not try 4 mm

[MatsP]

This www.poseidons-palace.co.uk/Poseidons_Aquariums/Aquarium Safety Calculator.xls.htm
seems to say you can do that with 3mm glass (with a safety factor of 3!). However, like Bas, I wouldn't go for less than 6mm glass. It won't make a huge difference in price, and it's a LONG tank even if it's shallow.

I do believe 5mm glass is "available", because typical commercial tanks (e.g. Hagen Fluval, Juwel, Eheim/mp, etc) are made from that. But most custom tank builders use 4mm, 6mm and 10mm glass - and of course thicker glass for really big tanks. I think this is mainly because if it's not strong enough with 4mm, the extra thickness in 5mm only goes a little further. There is 8mm glass available as well, but again, the step from 6 to 8 is only 25% extra strength, where 10mm is only a little bit more, but gives a 40% increase in strength over 6mm. I have 4ft x 15" x 24" (L x H x W) tanks made from 6mm glass, and other tanks of similar size made from 10mm glass. The 6mm tank has a 10mm base, and uses a cross bar in the middle of the tank, which the 10mm glass ones haven't got.

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Mats

[Bas Pels]

In NL 6, 8, 10, 12, 15, 20 mm glass are standard

4 mm might be available, but as the glass is produced @ 6 * 3 meters - roughly 20 * 10 feet, the 4 mm glass might be too thin to handle in the factory

But I'm afraid I'm getting a bit carried away, after all the questions related to somewhere in the USA

[MatsP]

after all the questions related to somewhere in the USA

Or even Canada!

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Mats