View Single Post
  #5   Report Post  
Old 03-08-2005, 12:34 AM
George
 
Posts: n/a
Default


"JGW" wrote in message
...
We're getting ready to build our new pond. The contractor wants to
line the walls and bottom with rocks, which he says will serve as a
great huge biofilter. I have read that it's impossible to keep the
pond clean with rocks on the bottom, and that they can trap hydrogen
sulfide gas.

What are your thoughts?

Thanks.

Joan
___________________


Some use rocks, some don't. Whether it traps hydrogen sulfide depends on
the nature of the material used. Obviously, if you create a thick silty,
clayey bottom, there is a definite possibility that H2S build up will
occur. If, however, you have good water flow, use large pebbles or rock in
a thin layer (I use 1/2"-3/4" natural-color rounded quartz/chert pebbles in
a thin layer more for appearance than anything else - also the fish like to
root around in the rock), have good filtration, and good biologic growth,
and regularly maintain your pond, you should have no problems. I think the
rock gives it a more natural look. On another note, if your pond is prone
to heavy sludge build up, cleaning can be tedious, and usually involves
scooping up the rock and rinsing it, then cleaning the bottom. Frequent
use of aquazyme or similar products can significantly reduce sludge build
up (the source of sulfide-reducing bacteria).