Drain questions

[mike31154]

Many tank manufactures offer tanks with plastic/acrylic overflows siliconed to the glass walls of the tank itself. I reckon the reasoning is that typically your overflow is not subject to the same stress and pressure of containing, say, 90, 120 or more gallons of water. And as you suggested, if the seal is compromised, it's not necessarily a disaster in the making. If it's a good silicone job, there should be no problem.

The only other issue I'm aware of is the different expansion rates of acrylic vs glass. This can cause a seal to eventually fail when subjected to large temperature changes on a regular basis. When I build the sump for the 90 I plan to set up, I was thinking I may use acrylic for baffles (plan to use an old 65 gal glass tank). Instead of trying to silicone the acrylic in, I thought I might silicone two narrow pieces of glass on each side, thereby creating a sort of slot to slide the acrylic into. Of course a perfect seal is not really required here, whereas for your application, you'd likely want something with a little more integrity. Could still apply silicone to the acrylic before sliding it down the slots though.