I've been pricing out different ways to build a 480 gallon aquarium. For large projects, plywood is definitely cheapest but it occurred to me that I could buy .75"x36"x86" of plastic, probably pvc, sheeting for a somewhat reasonable price. after you figure in the cost of sealing the plywood, I can't imagine the cost difference is that large. Has anyone tried this? It'd absolutely need to be braced. I'm honestly not worried as much about aesthetics because this is getting set into shelves and the actual pvc wouldn't be visible. My main concern is bowing and whether I'd need supports, in addition to cross bracing, outside the pvc. Has anyone heard of anyone doing this? Obviously, there are also concerns of plastacizers leeching into the water but I've already reached out to a couple manufacturers about that.
I have built many large aquariums for Zoo’s. We tried a PVC sump once but found it to have issues with bowing and needed extra support. So we just continued with Plywood. You have to be a pretty good carpenter to do this thou. Lots of bracing and such needs to be done. As water loves to find weakness.
I "think" the stuff expands & contracts depending on temps ? Don't know if that would make a difference .
It might be possible to use PVC with the right bracing system. Outside bracing and cross bracing is dependent on the tank dimensions but with PVC as a tank material outside and cross bracing would be needed. I think that the cost of a PVC tank would be rather high as the bracing system required would basically need to be another tank that the PVC sits in. I am guessing that the PVC sheet would likely cost more than a quality epoxy for a plywood tank. Another concern I would have is the installation of the viewing panel. A pressure seal might work. Other material options other than plywood would be FRP, HDPE tanks. I used plywood for my tanks because the epoxy absorbs into the wood and creates a waterproof shell. When fiberglass is used in conjunction with the epoxy it will also provide further reinforcement to the structure. I did add a PVC bottom to one of my tanks but it does not act as a water seal. If you are not looking to have a side viewing panel and just want top down then I would look at HDPE tanks. Open top HDPE tanks require bracing in larger sizes but they are readily available. I use a 265gallon and 120 gallon HDPE tanks for my sumps.
