Edward wrote:

I have been reading some about ammonia, nitrites, algae etc. and it
appears that no effort is made to maximize the removal of ammonia
using filters for fish pond owners. I have been doing some research
on the removal of nitrates for individual (home) wastewater treatment
systems for environmentally sensitive areas and believe the
intermmitent sand filter would be of use for fish ponds. There are
many sites on this topic and here is a sample of what is available:

http://www.wisc.edu/sswmp/pub_15_24.pdf
http://www.septic-info.com/doc/display/59.html
http://www.extension.umn.edu/distrib...es/DD7670.html

In 1999 research produced information on the best operational methods
for the conversion of ammonia to nitrate and then nitrate to nitrogen
using the intermittent sand filter, a very stable and reliable
treatment method.

The problem is, most of us aren't _fish_ pond owners (some are, but I'm sure
not the majority). We're water gardeners, who may or may not keep fish.
So we really have no interest in nitrification. We need to control ammonia
- and if you've been reading here and got the impression that "no effort is
made to maximize the removal of ammonia", you've been reading the wrong
posts - but we don't even _want_ to remove nitrates. Nitrates feed our
plants.

Sand filters (intermittent or otherwise) also tend to take quite a bit of
power - not really worthwhile for garden ponders.

Finally, there are serious potential hazards with any nitrification
processes. If you're not careful with it you'll end up with H2S and other
sulfurous gases, so I rather doubt the claim for "very stable and reliable"
treatment in the small system.
--
derek