I started my tank about 5 weeks ago and let it run for 3 weeks after adding some food to start cycling. I then tested my waters and had good nitrite readings ( 0 ppm). So I added 6 spotted corys. After 1 weeks the nitrites went back down to zero so I added a GBR which had no effect on the water. This past Friday I added 6 lemon tetras and the nitrites sky rocketed to between 2 and 5 ppm. I have been doing daily water changes and adding some of the tetra safe stuff that helps with taking away the toxicity of things. Is there anything else I can do to help with this. The corys and the tetras are pretty hardy, but I am really worried about my GBR.

I have a 20 gallon long with 8 assorted plants ( Swords, moneyworts, and luteas). I have a marine land 150 biowheel as well as a hagen fluval 105 running mostly biomax.

stop adding food untill the nitrItes go down.

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

That is too small of a tank to add that many fish at once. You should add no more than 1-2 per week. Cories are not very hardy and will not take toxic water for very long. I would be doing daily 50% water changes until you got it under control.

Doesn't sound like your tank was fully cycled before you started adding fish. Are you using an API liquid test or strips? Strips are very well known for being inaccurate.

I am using liquid api drops, just hard to distinguish the upper level of the nitrites, the purples are very close.

Adding the Tetra SafeStart is a good idea but you shouldn't have to keep adding it - just dump one bottle in and that's it.

As bob mentioned, stop feeding. Keep on those water changes as well, and don't vacuum your gravel - doing so will kick up any debris that may have settled into the substrate and will elevate your ammonia, nitrite, and nitrate concentrations. Instead, let the plants sink their roots into the substrate and let them do their thing.

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Officially fishless until after the move....tune in later for details!

this is what I use and works very good for me

Ecological Laboratories
Microbe Lift TheraP for Aquariums
Ecological Laboratories TheraP for salt & fresh water will provide a natural aquarium ecosystem, for better overall fish health and improved water quality. TheraP is chemical free and increases resistance to pathogens and parasites.

Features:
- establishes and maintains symbiotic microbial populations
- biologically supports a healthy aquarium eco-system which results in a beneficial breeding environment
- stimulates fish's immune system
- promotes fish growth
- improves dissolved oxygen levels
- aids respiration and gas exchange
- oxidizes both ammonia and nitrites, also reduces nitrates
- reduces environmental stress
- digests fish waste
- seeds and helps maintain biological filters

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55 Gals. Plants Anubias,Amazon Swords and more. Tetras: 6 Sarpaes.4 Red Eyes,5 Black Skirts,4 Giant Danios,2 Lemons, 2 Emerald Cory,4 German Blue.
10 gals. tank : Plants, Full of Guppies; 20 Gals. Tank planted Full of Guppies: 1 gal tank filled with Guppies