Re: [F] duck weed lowered nitrates

In article <1994Jan18.182245.9696@bme.ri.ccf.org> you write:
>I have gleaned several good bits of help from this group, 
>so here is my contribution.
>I have a 29 gallon freshwater tank that has been going for about 
>18 months with 1 large angel, 1 6" pl*co, 1 large gouramie,
>2 dwarf gouramies, 2 swordtails and 2 platies.  UGF with 2 powerheads,
>plastic plants, some algae controlled by pl*co and occasional glass 
>scraping.  20% water changes twice a month with gravel vacuuming.  
>Lighting: one plain old PlenPlax fluorescent. (20-40 watts?)
>After loosing 2 dwarf gouramies, I checked the ammonia (0) and 
>nitrates (> 150 ppm!) Started twice weekly 20% water changes and 
>reduced feeding.  This brought nitrates down to 40-50 ppm, where they 
>stayed fairly constant after several weeks.  Maintenance resumed at 
>about 3 times a month.  
>I wasn't very happy with this level of nitrates, so I decided I needed 
>something to eat the fertilizer.  I bought a couple of scoops of 
>duckweed, performed daily rinses and complete water changes for a week
>in a quarantine bucket with shop light, then dumped it in the aquarium.
>Nitrates are now constant at less than 5 ppm (detection limit of 
>Aquarium Pharmaceuticals dry tab tester.)  I harvest about half 
>the duckweed during each maintenance.  It pretty much covers the 
>surface by the next time.
>Simple, easy. Happy fish, happy aquarist.