NaClFinatic
05/12/2006, 04:21 PM
I have been reading about use of plenums and it seems like a good idea. But previously I had seen ones completely trapped under the sand. Yesterday I looked at plenum plans on the GARF site and found their diagram with a tube rising out of the plenum and a pump attached to this. They say to use this riser and run the powerhead until Amonia and Nitrite are gone. They also reccommend a relatively shallow sand bed on top of the plenum.
Does anybody know if the powerhead is intended to pump water into or out of the plenum? And what is the purpose of initially circulating this water? I thought the plenum should be relatively free of circulation to create the anaerobic environment.
How deep does the space really need to be? They seem to usually be 2" simply because it is eggcrate on top of 1" PVC, but could this be lessened?
Does anyone with experience with a plenum have any other reccommendations? How deep should the sand layers on top of the plenum be? Have you used extra screening layer to keep the lower sand from being disturbed or have you skipped this step?
Thank you
Does anybody know if the powerhead is intended to pump water into or out of the plenum? And what is the purpose of initially circulating this water? I thought the plenum should be relatively free of circulation to create the anaerobic environment.
How deep does the space really need to be? They seem to usually be 2" simply because it is eggcrate on top of 1" PVC, but could this be lessened?
Does anyone with experience with a plenum have any other reccommendations? How deep should the sand layers on top of the plenum be? Have you used extra screening layer to keep the lower sand from being disturbed or have you skipped this step?
Thank you