Hi JackdaWack
I have a under gravel pump in my res.It sucks up the water and jets it out
an adjustable outlet.I got this pump when I had a fish tank set up.You can
buy it at wally world for around $20.00.It has a tube you cut to fit your fish tank to suck water from under the gravel and jet it out over the top of the water level.Its great in this 39 gal. tub with 10 gals water & nutes Iam setting up to start a grow soon.That pump and a 12" air stone gives me alot O2 in the res.I put a small piece of panty hose around the intake of the pump this helps in two ways , one it filters the pump and two you will see how much of your nutes are not mixing or whats been used.Let me know how you solve the problem. Peace :what: