CO2 Retention with A Sump


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
I wish to use a 55 gallon aquarium as a sump for my tank. My biggest concern is how to provide a seal to prevent CO2 leakage at the joint. I can work the drain/return lines well enough, but how could the seal be made, without using silicone, or the ole reliable duct tape? It seems, to my mind, that I'm trying to create a 55 gallon canister filter! All comments appreciated! Thx in advance. :D :D :D



Junior Poster
Jul 27, 2007
I use the Glad Press and Seal on my sumps and on the tops of my tanks to seal them. Here is the link: GLAD Press'n Seal® Wrap

I started to use it because of water evaporation during the winter (really dry in the Southwest) and it works great. You can tear or double up over the strange bumps (like return lines), and it is pretty forgiving with taking off and sticking it back to the sump.

You do have to replace it every so often, but a large roll has lasted me well over 6 months with sealing 5 tanks and two sumps. Hope this helps! :)