nitrite spike, what am i doing wrong?

When cycling a tank the first spike to happen is the ammonia spike. The second spike to happen is a nitrite spike. Once more bacteria has time to grow your nitrites will again shrink back to zero (sometimes overnight) and then you will show nitrates in your tank. Essentially speaking your cycle is just in the second phase, but you need to keep doing water changes to keep the nitrites down as much as possible. I believe 1.0 ppm is much too high and you should get it closer to 0.2 ppm or less.

Maybe lose the ammonia media. All it's doing is ammonia from the bacteria you're trying to feed. As the media wears out, your bacteria will have to catch up to the ammonia that the media used to be adsorbing.

When you clean your filters, make sure you clean one thing at a time. For the aquaclear, I would only keep sponges and have two in there. So, one week you clean one sponge and the second you clean the other. This way you don't run a risk of killing off the bacteria. I do my tanks this way and it allows me to rinse the sponges under tap water.

How big is the tank and the fish load?

Just a couple of thoughts, one is remove the ammonia absorbing media, watch you levels and do water changes as you have been, also I have heard nothing good about "cycle" and a lot of bad things. based on what I've heard ( never tried it myself) save your money. if you are through the first stage of the cycle, and your fish load isn't high you won't see ammonia on your test kit. if you are reading nitrites this is probably where you are. just give it time keep up the water changes to keep your fish comfortable and eventually things will be OK. As far as washing the media in tank water, that technically shouldn't have hurt anything, but I typically don't mess with anything until a couple of weeks after the cycle.

I am with daveedka. 4-6 weeks for the typical cycle is a guideline only. Sometimes faster and sometimes longer. I have talked to folks whose cycle took 8 weeks. Hang in there-it will get there.

I did a fishless cycle with pure ammonia and had a nitrite spike I couldn't get rid of. I did 90% water changes (as much as I could suck out of the tank) 2 consecutive days and got rid of my nitrites alltogether so I wasn't sure if this was normal or the result of me adding too much ammonia and the bacteria couldn't keep up. Being that you're doing a fishy cycle, I can't say for sure but try to do a little larger water change and see what happens. You should be fine with a 50% change with the lemon tetras but I'm unfirmiliar with the pleco you have. I can't see the large water change being any worse than nitrite poisoning though. Kyle

I agree, a larger water change to reduce nitrites is in order. Otherwise, being patient will help. I wouldn't add anymore of the Cycle, as it isn't introducing the bacteria that the tank needs. If you can find Bio-Spira, it will help, but removing the ammonia-reducing media and keeping up the water changes will also work.

If you continue to have problems, have your test results confirmed at your LFS.

I think the 'pit bull' pleco is likely a bulldog, or rhino, or rubber lipped pleco. Creative naming by LFS doesn't help the hobby.