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Tank Design


Pygmy Octopus
Dec 9, 2005
I have been reading quite a bit and am ready to ask a few questions.

I am going to build a customized DIY tank that will be at least 50g. Is there a preference between tall and narrow, or shallow and wide?

The tank will have a customized acrylic lid that will fit snuggly onto the top lip and have locking latches for security.

Plumbing will be through the bottom. I will drill two 1.5 inch holes, one for drain, one for return...will need to sort out some sort of check valve for the drain so that I don't have a flood on my hands of the pump dies or the power goes out.

Will drain to a sump housing a Euro Reef skimmer (which I am also considering DIY - anyone built a DIY skimmer that's worth a damn?).

My problem will be keeping the thing cool enough. In San Diego we get some rather warm summers - I have problems keeping my 125g reef tank under 80 degrees in the height of summer. I will probably need a chiller at some point, although I do not relish plunking down that sort of cash.

I am asking for input. What is the best design you have ever seen/thought of? I am taking my time with this, so give me your thoughts.


Dave in San Diego
Don't put your plumbing through the bottom of the tank unless you have a standpipe that goes up to the water level. A check-valve is a mechanical device that can and will fail after a given amount of time. Most aquarium check valves are designed to prevent a backflow of only a few gallons and would probably fail brand new under the weight of all the water in the tank.

Other than preventing a flood that truly is inevitable, the other reason to have the drain high is so that it skims the surface water, because the things you're trying to take out of the water naturally accumulate there.

Its also generally considered safer to drill the glass on the side panes closer to the top. There's a whole lot of stress on that bottom pane and drilling holes there isn't a good thing. Production tanks that are drilled in the bottom are tempered after drilling to make them stronger.

Good point re the stand pipe - to say nothing of the comments about the stresses on a bottom panel vs. a side panel. After further thought, I am now considering a overflow box at the back of the tank - that will still require a draing hole to be drilled on the bottom panel....

Regarding "tempering" the bottom panel. As this tank will be made of acrylic, does the tempering issue still apply? If strenght is an issue, then I can always make the bottom panel out of 3/4 inch material. That should be sufficient, wouldn't you think?

What about tall(er) and narrow(er) vs. shallow and wide question? Do you know if there is a preference wrt a bimac?
If its acrylic then the drilling issues aren't quite as severe--it will bend a little bit where glass would crack. Just make sure your acrylic is thick enough, and consider "euro-bracing" around the top. I've never worked with acrylic, so I can't give advice on thickness. If you're doing a DIY tank out of acrylic, I would recommend what's called an external horizontal overflow. This is a way to make your display tank more attractive by removing internal boxes and plumbing, but also easier to octo-proof. It involves building the overflow box on the outside of the aquarium and then cutting teeth in the side of the tank to flow into it. I'm on a dial-up connection and can't dig for the link right now, but go to google and type this in: "site:reefcentral.com external horizontal overflow" and you'll get a few truly excellent threads about how they work. Those threads will be about doing this with glass tanks, but if you do it with acrylic you have so many fewer question marks with regard to safety.

As for the shape of the tank, I would think shallower and wider would be better, but I hope other people weigh in, too.


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