Question about cycling

[severitis]

I have been trying to find an answer to my cycling question, but haven't come across one yet. I started a 90 gallon marine tank 4 weeks ago with cured live rock and live sand. 3 weeks into the cycle my readings were .25 ammonia, .0 nitrite, 0 nitrate. So I added 6 damsels. After 4 weeks my readings are .25 ammonia, o nitrite, and 0 nitrate.

Should I do a water change? Is my tank cycled? The first test was done at fish store, I believe he used api kit. The second test was done at home with api test kit. Not sure why levels aren't changing.

In my sump I am running 150 skimmer and bag of phosguard. Live sand 3 inches.

Any insight you can give me would be great. Thanks.

 

[dreaddinit]

The best I understand it, your still going through your cycle. If your still seeing ammonia, your still cycling. Im not sure on the water change though. I would guess probably not.

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[scooter31707]

Did you keep track of your cycle, meaning did you see ammonia, nirite, and nirate all rise and come back down. Also how did you jump start your cycle? If you saw the cycle be completed, then it's your test kit. API is known for giving a false ammonia reading of 0.25ppm. May want to try a different test kit.

 

[GimpyFin]

It doesn't sound like your tank is cycled. Were you using anything as an ammonia source during those 3 weeks? You would need that or an alternative like biospira (Bacteria) to get the tank cycled. Once Ammonia and nitrite spike and go back to zero, you should see nitrate grow. At that point your tank is generally cycled. If you are choosing to cycle the tank with fish, adding 6 damsels at once is a lot with a new or relatively unestablished biofilter, even in a 90g.

 

[tazdvl]

I have a API test kit that ALWAYS shows .25 ppm ammonia. I would not trust the API test.

 

[ktownhero]

A cycled tank will never show ammonia. Make sure you have an accurate test.

 

[DePinchGonze]

Once your ammonia reads zero your nitrites will spike, I usually wait for them to drop off then do a water change to bring nitrates down, then add livestock slowly so your new biological filter can keep up

 

[CStrickland]

Cured live rock and live sand can have plenty of bacteria to prevent a cycle. Also, it would be funny to have no nitrite if you actually had .25 ammonia. But 6 fish is a lot at once. If it were my tank I'd probably try a fancy test at least once. Maybe a diff fish store would confirm with a diff brand.