Potts050;2329357; said:I built one like that about fifteen years ago with a shower head and a five gallon plastic paint pail for my discuss tank. It was one of the best filters I ever made. I used lava rock mulch for the media. After about two months I decided to do a water test prior to a water change to see how my nitrates were. They were impossibly low. Barely detectable as I recall.
I figured that there must have been anaerobes living at the center of the lava pieces eating the nitrates! I tore the tank down a couple of months later because I got transfered through work and never did figure it out completely. How do you deal with nitrates on this tank. I don't imagine they're a problem in your green house...
The only difference from the shower head is that the bar rotates, so the water is spread thru all the bioballs. Thats the beauty of this filter.

I almost dont have nitrates. And I do water changes frequently.
In the greenhouse I dont have any problems with nitrates.
