Nitrite Spike How Much Does Prime Detoxify?

Ugh, so I'm in the middle of a Nitrite spike as well. I changed all my gravel Monday evening, did a 50% water change, and all seemed well. Tuesday morning all the fish were gasping for air at the surface and nitrites were at least 5ppm. Strangely ammonia was and is still at 0. I added a 5x dose of Prime + aquarium salt and things improved significantly. Last night the nitrites were still very high, so I did a 65% water change and added nitrifying bacteria. Now it's down to 0.2ppm. Not sure if the reduction is due primarily to the Prime or the water change, so I'll plan to continue daily water changes until things stabilize.

 

Ugh, so I'm in the middle of a Nitrite spike as well. I changed all my gravel Monday evening, did a 50% water change, and all seemed well. Tuesday morning all the fish were gasping for air at the surface and nitrites were at least 5ppm. Strangely ammonia was and is still at 0. I added a 5x dose of Prime + aquarium salt and things improved significantly. Last night the nitrites were still very high, so I did a 65% water change and added nitrifying bacteria. Now it's down to 0.2ppm. Not sure if the reduction is due primarily to the Prime or the water change, so I'll plan to continue daily water changes until things stabilize.

First problem is that by "replacing" all your gravel, you removed all the nitrifying bacteria that were growing on it and have essentially extended the amount of time your cycling is going to take! When you are cycling a tank, nitrifying bacteria are establishing on every surface in the tank and the filter. Removing anything also removes the bacteria on it. The food for that bacteria is in the water in the form of ammonia and nitrites. When you remove some of the bacteria that "eats" Nitrites, your nitrite level will rise- that's what you're seeing. So the rule is: when cycling a new tank, remove nothing from the tank except water and free floating debris. Oh, and Prime will not decrease the measurable level of nitrites or ammonia in a tank because it doesn't actually remove it. It just inactivates it somehow-but the nitrites and ammonia remain in the tank for the bacteria to use. Your drop in nitrites was a direct result of the water changes. *Sorry I edit a lot because the auto-speller is dumber than I am!

 

Only do enough water changes to keep your nitrites at 1 ppm or less. You need the nitrites in there to feed the bacteria that will ultimately "eat" ALL the nitrites your tank produces. Your ammonia oxidizing bacteria (AOB) has evidently established in a large enough quantity in youe filter media and on other surfaces that replacing the gravel had no effect on its ability to oxidize ammonia or you would have had an ammonia spike as well! Your tank is progressing. Be patient! You did replace the gravel with another substrate right? If not, I recommend doing so. You need the surface area for bacteria colonies in the tank while it's cycling.

 

Only do enough water changes to keep your nitrites at 1 ppm or less. You need the nitrites in there to feed the bacteria that will ultimately "eat" ALL the nitrites your tank produces. Your ammonia oxidizing bacteria (AOB) has evidently established in a large enough quantity in youe filter media and on other surfaces that replacing the gravel had no effect on its ability to oxidize ammonia or you would have had an ammonia spike as well! Your tank is progressing. Be patient! You did replace the gravel with another substrate right? If not, I recommend doing so. You need the surface area for bacteria colonies in the tank while it's cycling.

Thanks for the thoughtful reply - yes, I actually replaced light gravel with dark gravel (and boy, does it look better!). Makes sense that the nitrites spiked but not ammonia given the established filter media. In the course of this, pH also decreased from 7.5 to 7 and Nitrates increased from ~0 to ~40 (this was before last night's big water change). Ok, so I won't change more water right away unless Nitrites get back above 1, or anything else goes wrong. Will continue regular testing though...

 

Quick update - I didn't change water last night but did add another dose of nitrifying bacteria. Nitrites are down to 0.1 (from 0.2) now, so I think I'm in the clear. Shew!