I guess I caused it to mini cycle?

[Christina]

new SW fish tank (5 months old) Clean the filters?

That was a few weeks ago. I jumped in and cleaned 2 of the filters, and replaced the other two, adding carbon to the 4 media containers.

Then one week later added a skimmer, and did my water change of 20 gal. But was horrified to find I had a nitrite reading. It was .25 The water changed brought that down.

Fast forward to today. Nearly a week later. Was away for about 36 hours and one of my fish looked odd. The yellow tang looked to have torn a fin. I tested and have another reading on nitrites. Not to 025 yet, but def not 0 either. The nitrates are at 10 ppm (with the api test) (but 20 ppm with the jungle lab quick dip) PH is 8.4 (a touch hiher than the usual 8.2 I had been getting) Ammonia is 0 ppm.

I just mixed 20 gal of water and it has a pump in it so that I can do another water change soon. I wasnt expecting to do one again so soon, as I usually go three weeks.

Another change I made was in the feeding of the tangs. I bought three different types of the sea weed, which I am giving them twice a day now, and bought some more frozen marine foods to varie the diet more.

So, I guess I just wait, and do water changes until the tank stabilizes again. I reread Leebeca how to make a water change sticky again to be sure I am doing everything I should.

So far everyone else in the tank looks great.

I could use any more advise. I get a bit stressed when I feel my fish are stressed.

Thanks
Christina

[ToddTT]

I'd do water changes until the nitrite is undetectable. Larger water changes will be more effective.

I'd also consider additives like Seachem Prime that detoxify nitrites in the meantime.

I'd limit feeding until you get nitrites back to 0 as well. Better that your fish are a little hungrier than usual, but not subjected to toxins.

Are any of your fish breathing rapidly? This is one possible symptom of nitrite exposure.

Keep an eye on your tangs. They may be inflicting damage on one another.

[Christina]

No rapid breathing for any of the fish. I hope it stays that way. I just but the salt water into mixing, so I have a wait a little while on the water change, will have to reassess in the morning. Other than the torn looking fin, Everything looks good, to me. Still pretty new at this, tank is 6 months old now. Ive seen some fish at the LFS breathing rapidly before right after he gets shipments, but mine look good to me.

Thanks,
Christina

[leebca]

There has been some reported problems with API test kits. Just to be on the safe/secure side, get another brand of nitrite and ammonia test kit. Try for a test kit line that is high profile like Salifert.

Your filter was apparantely doing a portion of your biological filtration. Slow changes are needed when this occurs, so as not to cause a crash.

Nitrites have a slow negative impact on fish health. High levels cause death, low levels for a length of time cause at least a shortened lifespan.