ok, so i am on some pain meds for a sprained shoulder and they make me really hyper and uber focused. almost as if they are cut with riddalin (spelling??whatever) anyway, to the issue at hand:

i was doing my weekly water test on my tanks and my over populated 29 gal, all levels are cherry. however, in my appropriately populated 20 gallon, which water i have recently changed, had nitrite levels in the danger zone (5.0 ppm) on my test kit. i did a quick water change of 30 % which is more than usual, and included a minor substrate cleaning. i changed the filter and let the water settle while i was at work, when i got home i retested i got lower levels of nitrite but not significantly (3.5-4.0 ppm). what do i do?

my 20 gal tank care habits so far:
-feeding minimal food 2x daily (1/2 tsp flakes, 1 med shrimp pellet-am, 1 sm algae wafer-pm, 1 mL defrosted bloodworms)
-aquarium salts per direction
-bimonthly water changes and tank wall cleaning with AmQuel ammonia neutralizer, aqueon water conditionor and nutrafin Cycle bacteria
-monthly filter changes
-monthly plant and decor cleaning (fake plants)

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RIP "whitey" my albino pleco. found dead 5-21-12

29 gal- 2 leopard ctenopoma / 5 tiger barb / 5 corydoras catfish / 1 golden weather loach / 1 three spot gourami / 2 bolivian ram / 1 juvenile bristlenose pleco / Amazon sword / Java fern / Red Ludwigia / Wisteria / Anacharis
filtration- AquaClear 50, QuietFlow 20; 325 gph total

20 gal- 1 clown pleco / 8 black neon tetras / 1 neon dwarf gourami / 4 Asian glass cats / 5 green corydoras catfish
filtration- QuietFlow 30; 200 gph

You * should* be changing the water out weekly not bi monthly. Sounds like it's building up in your tank. Live plants would also help.

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"Being ignorant is not so much a Shame, as being unwilling to learn".-- Benjamin Franklin

weekly, not every two weeks? ok, i'll give that a try. thanks! i am reletavely new to the hobby and am saving toward a 55 gallon tank which i will live plant, but will def need help with that. i.e., how dense, what plants, fertalize? nutrients? substrate specs? all questions i will ask and research once i have the tank $$.

__________________
RIP "whitey" my albino pleco. found dead 5-21-12

29 gal- 2 leopard ctenopoma / 5 tiger barb / 5 corydoras catfish / 1 golden weather loach / 1 three spot gourami / 2 bolivian ram / 1 juvenile bristlenose pleco / Amazon sword / Java fern / Red Ludwigia / Wisteria / Anacharis
filtration- AquaClear 50, QuietFlow 20; 325 gph total

20 gal- 1 clown pleco / 8 black neon tetras / 1 neon dwarf gourami / 4 Asian glass cats / 5 green corydoras catfish
filtration- QuietFlow 30; 200 gph

Nitrite is the second stage in tank cycling. In a normal tank these levels drop after several weeks of cycling. Make sure your measured nitrite values are correct. If they are, then you may have organic material decomposing in your tank, stop feeding and look for dead fish in your tank. Also, make sure your tap water doesn't have ammonia or nitrites in it.

my tap water is clean. i tested it before i cycled the tanks. but it would be a good idea to retest, thanks. i just tested the tank now, and it is between 1 and 3 ppm i will reduce to one feeding of the same size daily for a few days but all fish are accounted for. thanks all for your help. will post results in a few days.

__________________
RIP "whitey" my albino pleco. found dead 5-21-12

29 gal- 2 leopard ctenopoma / 5 tiger barb / 5 corydoras catfish / 1 golden weather loach / 1 three spot gourami / 2 bolivian ram / 1 juvenile bristlenose pleco / Amazon sword / Java fern / Red Ludwigia / Wisteria / Anacharis
filtration- AquaClear 50, QuietFlow 20; 325 gph total

20 gal- 1 clown pleco / 8 black neon tetras / 1 neon dwarf gourami / 4 Asian glass cats / 5 green corydoras catfish
filtration- QuietFlow 30; 200 gph