I used 4" x 24" for mine. Seems to be fine, but my tank is only 75G.
I used 75' of 1/4" O.D. tubing(1/8 I.D., i think) coiled inside the pvc.
I like the idea of having it on the outside of the PVC, because it leaves my room for bio balls in the center, and more room for the bacteria to do its job. Just make sure you use tubing that blocks light, or algae will be a problem.
I have read about people using multiple coils and a single output, but I cant say if its good or bad. My coil is one continuous feed of 75'. The main goal of the tubing is to allow proper surface area for the aerobic bacteria to consume up all the O2.
I built mine on March 9, 2009, so its only been going for a little over a month and a half. The effluent water is showing zero nitrates, so it is working, but the tank water still has ~20 ppm nitrates.
I have been struggling with the proper drip rate. It seems hard to find a good balance where I don't get the rotten egg smell , but still show 0 nitrates on the output. But I thinks its getting better as time goes on. In the early stages, it took out all the nitrate, but only at drip rate of 1drip/sec. But I still got the rotten egg smell. It seems that I am now able to speed up the drip rate a little more and still get good results. IMO, building 2 of them would be more efficient, because you filter through twice as much water at the same time, but I have read that using multiple coils in the same unit will allow you to speed up the flow rate as well. So I really don't know which is better.
Oh yeah, as far as coiling the tubing, its only save space, its the length that matters, not the shape of it.
Hope this helps. I'm not an expert on these, as mine is still pretty new, but I have read almost every article out there on them.
I used 75' of 1/4" O.D. tubing(1/8 I.D., i think) coiled inside the pvc.
I like the idea of having it on the outside of the PVC, because it leaves my room for bio balls in the center, and more room for the bacteria to do its job. Just make sure you use tubing that blocks light, or algae will be a problem.
I have read about people using multiple coils and a single output, but I cant say if its good or bad. My coil is one continuous feed of 75'. The main goal of the tubing is to allow proper surface area for the aerobic bacteria to consume up all the O2.
I built mine on March 9, 2009, so its only been going for a little over a month and a half. The effluent water is showing zero nitrates, so it is working, but the tank water still has ~20 ppm nitrates.
I have been struggling with the proper drip rate. It seems hard to find a good balance where I don't get the rotten egg smell , but still show 0 nitrates on the output. But I thinks its getting better as time goes on. In the early stages, it took out all the nitrate, but only at drip rate of 1drip/sec. But I still got the rotten egg smell. It seems that I am now able to speed up the drip rate a little more and still get good results. IMO, building 2 of them would be more efficient, because you filter through twice as much water at the same time, but I have read that using multiple coils in the same unit will allow you to speed up the flow rate as well. So I really don't know which is better.
Oh yeah, as far as coiling the tubing, its only save space, its the length that matters, not the shape of it.
Hope this helps. I'm not an expert on these, as mine is still pretty new, but I have read almost every article out there on them.
