We set up a dead water plenum in our 180 a while back and thought we'd share our set up and see if anyone has any advice or feedback regarding their plenums. I may not get all the chemistry right, so please let us know.
In a sense a dead water plenum is just a place where water can accumulate and develop the anaerobic bacteria to break down nitrates and nitrites. It is just an empty space under the sand bed that critters can't get to and stir up.
We've had the DWP set up since July and have a pretty good bio load on it. Our Nitrates peaked at 60 ppm initially and then soon dropped once the bacteria established. Since the drop we've added to our stock and our Nitrates and Nitrites have remained at 0 since. We do run a 40 gallon sump with 25 gallons filter floss, puragen phosguard, chemipure, and a full size skimmer. I don't attribute all water levels to the DWP but I think it helps.
The set up:
We lay 1/2" PVC diagonally across the bare bottom and lay egg crate over the top. View attachment 15653
We use the finest mesh we can find and lay it over the top and around the edges. This is to keep bugs and sand from sifting through but allow water and dissolved gasses and bacteria to pass through. We used 70% UV protection Sun Shade. We added about an inch and a half of sand then lay one layer of screen (this can be window screen) to keep gobies, eels, shrimp etc from getting into the sand bed. We then added the final layer of sand, about 2 inches or contoured to fit the seascape. No pumps or airstones under the DWP to pull the water; nothing pulls detrius through.
View attachment 15655
They guy who taught me this had an 80 set up for 8 years with a DWP. He only ran a hang on back filter and small HOB skimmer. When we took apart the tank there were no dead spots and his Nitrates and Nitrites were zero.
Anyways, let us know if anybody has feedback or experience.
In a sense a dead water plenum is just a place where water can accumulate and develop the anaerobic bacteria to break down nitrates and nitrites. It is just an empty space under the sand bed that critters can't get to and stir up.
We've had the DWP set up since July and have a pretty good bio load on it. Our Nitrates peaked at 60 ppm initially and then soon dropped once the bacteria established. Since the drop we've added to our stock and our Nitrates and Nitrites have remained at 0 since. We do run a 40 gallon sump with 25 gallons filter floss, puragen phosguard, chemipure, and a full size skimmer. I don't attribute all water levels to the DWP but I think it helps.
The set up:
We lay 1/2" PVC diagonally across the bare bottom and lay egg crate over the top. View attachment 15653
We use the finest mesh we can find and lay it over the top and around the edges. This is to keep bugs and sand from sifting through but allow water and dissolved gasses and bacteria to pass through. We used 70% UV protection Sun Shade. We added about an inch and a half of sand then lay one layer of screen (this can be window screen) to keep gobies, eels, shrimp etc from getting into the sand bed. We then added the final layer of sand, about 2 inches or contoured to fit the seascape. No pumps or airstones under the DWP to pull the water; nothing pulls detrius through.
View attachment 15655
They guy who taught me this had an 80 set up for 8 years with a DWP. He only ran a hang on back filter and small HOB skimmer. When we took apart the tank there were no dead spots and his Nitrates and Nitrites were zero.
Anyways, let us know if anybody has feedback or experience.
