ammonia levels are up

[volcomkrew4life]

So the other day I bought an AquaClear 50 filter to add onto my 20 gallon tank because I only have a tetra whisper filter running. I have one Green Spotted Puffer that's about 2 inches long. SG is 1.020 and pH is 8.0. Normally my ammonia is 0, nitrites are 0, and nitrites are around 20ppm but I just tested after having the new filter on for a few days and my ammonia is around .25ppm - .50ppm, my nitrites are still 0, and the weird thing is my nitrates are now at 0. My tank has been running for about 7 months. Any ideas??

[Dadof4]

Yes, you took away about 75% of your bio filter when you switched filters so you are basically recycling your tank. Did you leave the old filter in the tank?

[BushFishRox]

Did you remove the old filter when you added the new filter? That is the only obvious reason I can think of.

[Pufferpunk]

Why are you using a FW filter for a SW tank? You would have been better off with a protein skimmer. Is there live rock in he tank?

[volcomkrew4life]

I left the old filter on...I'm not an idiot. And no pufferpunk I started him out with low brackish so I haven't added any liverock or anything.

[jjj5311]

possible to have contamination in the new filter, something from the manufacturer that brought up the ammonia?
Idk much about saltwater yet... but sounds like you should be looking at LR and a skimmer and returning that filter.

The live rock will supply the biological filtration that is similar to the filter media in FW and the skimmer will do the mechanical filtration needed for the tank.

Again i do not know much about saltwater but from what i have read and heard that is what i would do.

[sevenyearnight]

I remember when you were raising your SG, didn't you also have some issues with nitrites, or something to that effect?

Ok, my first question, and I don't remember if I asked you this previously, but what test kit are you using?

Are you using tap water as for your water changes? If so, double check the tap source as many water companies add ammonia along with the chlorine to form chloramines, which are considered safer than straight chlorine, but there will be free floating ammonia that can be as high as 1 ppm. It's something they add periodically, so they won't have consistent levels throughout the year.

[LilGreenPuffer]

Do you know a local hobbyist, maybe through the nearest reef club, who can supply you with some live rock that you won't have to cure before using? If they are reputable, you might be better off taking a chance on using un-quarantined live rock and risking a disease (possibly dangerous) than dealing with this ammonia spike (definitely dangerous). Of course I only suggest this as a possibility if you can find a highly reputable person who won't try to sell you rock from a diseased tank or who wouldn't recognize that his/her fish are showing disease symptoms. It would be risky, but if the ammonia gets bad, if might be your best solution.