Biowheels And Nitrates

	A helpful hint on nitrates-they can cause problems if the level gets
too high. I had a planted 29 gallon tank with 8 angels (probably too many). My
angels developed eye diseases, one went blind. After numerous attempts with
medications (unsuccessful) I measured the nitrate level; it was way off the
scale of the test kit. >140 ppm. Water changes brought it down and cleared up
the problems with the angels. Any time I forgot to do water changes and the
nitrate level went up the angels suffered. Perhaps the plants were utilizing
the ammonia only and what they didn't use was being converted to nitrates by
the biological filter.  

Gerry (in hot humid Ann Arbor where it's supposed to storm like heck in a
couple of hours).