HELP nitrite spikes going on 5 days (that I know of but under 8)?

Question

I am still going out of my mind with my nitrite levels.

Currently my Ammonia is still 0 (has been for over 2 weeks)

my Nitrate is now 0 (yesterday was between .25 and .50 ppm)

But my nitrite is still fluctuating between 2-5

I have been changing 15% of my water twice daily and it has not changed it at all....I test it before the change 5 minutes after the change and one hour after and the color is always between 2 and 5 dark purple.

I tested my water conditioner also (mixed with water and it came out 0 ppm just like the regular water. I have not lost any fish but I am worried that something is very wrong and this is just a symptom. Last week I lost a fish which was in a dive position stuck in the gravel (She was a molly) which made me test the levels only 3 days after my last test.

My tank is 55 gallons

3 platys

1 moly

5 guppies

1 cory catfish

1 small Clown Pleco

Did not fill tank all the way hoping to keep oxygen levels high.

Please help ....Thank you

Answer 1

How long have you had the tank set up? How did you do your water changes? You should try cleaning the gravel, and try doing one larger 35% water change every day. I would add aquarium salts to the aquarium as directed on the box, as these will help reduce the toxic levels of nitrite in your aquarium. Do not doing anything with the filter, let it get really dirty. You can also try using a nitrite remover in your filter media, like a product by fluval called fluval lab series nitrate remover. This will also help detoxify the nitirtes. Use an airstone in your tank, it will help produce more oxygen in the tank by added surface agitation.

Edit: That person was right to tell you not to vacuum the gravel with every water change if you are doing one that often. You can even wait 2 weeks to do one with the stocking list you have. I think you are just doing too many water changes for a tank that is not heavily stocked. Cut back to once a week maximum. If you want your fry to grow faster, cleaner water will do this, buy yourself a 15-20 gallon tank and use that for the fry. You can use a sponge filter, which are extremely cheap and great for fry, and a heater+thermometer. Very in expensive. You don't have to get a substrate for the bottom, just put a few hiding places for them to go. It can be so easy and cheap to maintain a fry tank, plus you will save money when you clean your tank as often as you need to. You won't be buying as many water conditioners, and other chemicals you add.

Answer 2

There has been Nitrite for the Nitrobacter bugs to feed on for only two weeks. They just haven't had time to grow a sufficient colony. Keep up the frequent, small water changes, be careful about practices  that might damage your bacteria friends,things like violent temperature changes or large amounts of chlorine. The bacteria need lots of O2 to grow,but keeping the water level low will not increase the O2 levels. Gas exchange takes place at places where the surface tension of the water column is disturbed, so a filter or power-head that disturbs the surface and perhaps makes a little noise (bubbles and gurgles) is providing as much O2 as your tank can hold.

Also you can reduce the number of tests you are performing,and if you feel the need to test after a water change, wait several hours so everything has had time to stabilize.

Be patient,and good luck.