apos
Member
To help keep my nitrates in check (they are hovering at around 20 give or take), I'm starting a super cheap DIY project: a remote deep sand bed. My current tank has a sandbed, but not one deep enough to provide much, if any, denitrification. I have some chaeto in the sump, but not enough room for a real fuge, and so little hope for that doing much either.
The basic idea of the rdsb for those that don't know, as outlined by Anthony Calfo, is to have a 5 gallon bucket or more filled almost completely with sand (the smaller the grain the better). You then pump water over the surface of the sand at a fast enough rate that nothing can settle on it (this is key to making it easy to maintain, unlike sand beds in display tanks, which cannot avoid this problem).
The water diffuses into the sand, eventually forming areas with little oxygen. This is where the denitrification (conversion of nitrates into nitrogen) can happen. The point is not to run water forcefully THROUGH the sand, but to let natural diffusion through the sand work its magic. The system is also kept DARK so that there is no worry of growing any algae or diatoms: the point is that we simply won't have to worry about maintaining this in the way we would about an in-tank dsb. All we're going for here is getting rid of nitrates (and a small increase in water volume and maybe buffering, depending on sand choice)
Materials:
+ tall 6 gallon bucket from LFS ($7.50)
+ 2 uniseal bulkheads, ordered online .75 and .5 size pvc respectively, ($2.30 and $1.30 respectively, plus shipping)
+100 pounds of Quickcrete playsand (very fine grain) from Lowes: ($3.78 a bag)
+Various PVC joints, pipes, and tubes (tbd)
+Either a cheap penguin 145gph pump, or a hagen aquaclear 50 to power system (already owned, but such powerheads can run in the 25$-35$ range)
That puts this project's ballpark cost at $18.66, not counting tax, shipping, plumbing, or powerheads. It would be less if you already had a bucket (some people use old salt buckets, though these were too shallow for my application), more if you didn't already have a powerhead, wanted lots of buffering sand, or didn't have lots of cheap piping equipment equipment floating around.
Tools:
Going to use a Dremel to file down the "ribs" on the bucket where the input and drains will be
Not sure about cutting the holes themselves yet: the holes need to be perfect, and I don't have the right dremel bits to cut the sizes I need. I may have to appeal to a hardware or plumbing store to drill them for me.
I also opted to buy 15 pounds of aragonite sand, just to get some extra buffering for my system in there. Not necessary (Expensive stuff: quite a ripoff, but what the heck can you do?), but can't hurt either. I don't know exactly how much sand will be needed to fill the bucket to the proper capacity yet: I almost certainly won't need all 100 pounds of the playsand. 5 gals can handle about 60 pounds, so I figure my 6 gal will take 72 pounds or more.
Note though that super cheap silica sand like this is okay for this application. We aren't going for looks, or worrying about microfauna burrowing. All we care about is tons of surface area: anything of a very fine grain will do.
I'll have pictures up as the project begins: just waiting for the uniseals to arrive via mail.
The basic idea of the rdsb for those that don't know, as outlined by Anthony Calfo, is to have a 5 gallon bucket or more filled almost completely with sand (the smaller the grain the better). You then pump water over the surface of the sand at a fast enough rate that nothing can settle on it (this is key to making it easy to maintain, unlike sand beds in display tanks, which cannot avoid this problem).
The water diffuses into the sand, eventually forming areas with little oxygen. This is where the denitrification (conversion of nitrates into nitrogen) can happen. The point is not to run water forcefully THROUGH the sand, but to let natural diffusion through the sand work its magic. The system is also kept DARK so that there is no worry of growing any algae or diatoms: the point is that we simply won't have to worry about maintaining this in the way we would about an in-tank dsb. All we're going for here is getting rid of nitrates (and a small increase in water volume and maybe buffering, depending on sand choice)
Materials:
+ tall 6 gallon bucket from LFS ($7.50)
+ 2 uniseal bulkheads, ordered online .75 and .5 size pvc respectively, ($2.30 and $1.30 respectively, plus shipping)
+100 pounds of Quickcrete playsand (very fine grain) from Lowes: ($3.78 a bag)
+Various PVC joints, pipes, and tubes (tbd)
+Either a cheap penguin 145gph pump, or a hagen aquaclear 50 to power system (already owned, but such powerheads can run in the 25$-35$ range)
That puts this project's ballpark cost at $18.66, not counting tax, shipping, plumbing, or powerheads. It would be less if you already had a bucket (some people use old salt buckets, though these were too shallow for my application), more if you didn't already have a powerhead, wanted lots of buffering sand, or didn't have lots of cheap piping equipment equipment floating around.
Tools:
Going to use a Dremel to file down the "ribs" on the bucket where the input and drains will be
Not sure about cutting the holes themselves yet: the holes need to be perfect, and I don't have the right dremel bits to cut the sizes I need. I may have to appeal to a hardware or plumbing store to drill them for me.
I also opted to buy 15 pounds of aragonite sand, just to get some extra buffering for my system in there. Not necessary (Expensive stuff: quite a ripoff, but what the heck can you do?), but can't hurt either. I don't know exactly how much sand will be needed to fill the bucket to the proper capacity yet: I almost certainly won't need all 100 pounds of the playsand. 5 gals can handle about 60 pounds, so I figure my 6 gal will take 72 pounds or more.
Note though that super cheap silica sand like this is okay for this application. We aren't going for looks, or worrying about microfauna burrowing. All we care about is tons of surface area: anything of a very fine grain will do.
I'll have pictures up as the project begins: just waiting for the uniseals to arrive via mail.
