After watching Dr. Tim's presentation on the advantages of a deep sand bed, I've decided to go that way. But having to bury 6 inches of expensive rock in order to maintain structure stability seems wasteful. My proposed solution is to drill my foundation rock and insert fiberglass rods as supports, so that the rods will be hidden by the sand, with only a fraction of an inch of rock actually embedded. Thoughts on why this would be impracticable?
Rock in a Deep Sand Bed
- Thread starter ubiq
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mandarin417
Active Member
Cut PVC and superglue it to your base rock. Use something like Marco cement to attach the PVC stronger to the rock. Use darker PVC to hide them in case some fish dig out the sand. See pics:
HuduVudu
2500 Club Member
The problem with DSBs is that they work on diffusion. Impediment of that diffusion causes lots of trouble. The PVC idea may seem like a good one but it will not allow diffusion. Anything inside of the PVC is dead and can not diffuse out.
Unobstructed diffusion is really important because the anaerobic portion of the bed needs food in and needs waste out. It is also acidic and will degrade calcium carbonate and sometimes form blocks. Movement of water through the different layers in the bed helps keep it healthy and fed.
It is my many years of experience with plenums that has taught me to not put rock work on top of these beds. One way that I found that works really well to get the advantage of the DSB without the issues associated with rock work is pictured here:
The plenum is in the 4" PVC pipe. My wife insisted on putting stuff on it and I explained to her that that was what the rock was for. :sigh:
This plenum provided calcium and alkalinity for wild caught porites and a stylo for five years, plus the other benefits of a deep bed. Over time I have found that though anaerobic beds provide de-nitrification it isn't that much. The stability of DSBs and plenums can be shocking to people not used to them. I rely heavily on that even today to keep my tank stable.
Unobstructed diffusion is really important because the anaerobic portion of the bed needs food in and needs waste out. It is also acidic and will degrade calcium carbonate and sometimes form blocks. Movement of water through the different layers in the bed helps keep it healthy and fed.
It is my many years of experience with plenums that has taught me to not put rock work on top of these beds. One way that I found that works really well to get the advantage of the DSB without the issues associated with rock work is pictured here:
The plenum is in the 4" PVC pipe. My wife insisted on putting stuff on it and I explained to her that that was what the rock was for. :sigh:
This plenum provided calcium and alkalinity for wild caught porites and a stylo for five years, plus the other benefits of a deep bed. Over time I have found that though anaerobic beds provide de-nitrification it isn't that much. The stability of DSBs and plenums can be shocking to people not used to them. I rely heavily on that even today to keep my tank stable.
