They work great for under a sump!! A couple of guys have them on here. You should get them for your build! I couldn't be happier with the whole outcome of the set up.
Haha, I admit it!
I am using dr tims one and only. I have never lost any fish with it, so it's worth it IMO! I lost fish in my qt because I didn't use it when I set it up...
Very cool. I'm using Fritzzyme Formula 9 (basically same as Dr Tim's). We'll have to compare notes. Are you upgrading from another tank or is this a clean new build?