Fishless Cycling, Water Changes, And Water Test Results

[cryslea]

Recap: been fishless cycling for two weeks, ammonia didn't budge, nitrites .25, nitrates 5 (same as tap). Did a 80-90% water change yesterday (yes, I remembered the water conditioner) per advice in a previous thread, turned up the heat a bit (can't seem to get it above 84). Added new ammonia to get it up to 4ppm. I was unable to remove filter media from a cycled (healthy) tank, but scraped off some algae/green growth from the filter into tank water, which I added to my tank. Probably didn't have much/any bacteria, but I didn't think it could hurt.

Today, my ammonia is unchanged (was expecting that), but my nitrites are now 0 and nitrates are 5ppm (same as tap- in other words, the nitrate did not eat my nitrite).

I know water changes will dilute ammonia, nitrite and nitrate, so while I'm disappointed to see a 0 instead of the .25 I'd had before, it's not a huge surprise. However, if bacteria lives in the filter and not the water, I'd expected to see the nitrite return to the previous level by now (it's been 24 hours since the water change). Was the assumption incorrect? During a fishless cycle, how long after a water change should the nitrite readings return? Does it take longer than 24 hours since I basically restarted the cycle?

Or... did I somehow kill what little, precious nitrite I had?

Either way, I have to wait now (good grief, fish-keeping is an exercise in patience!), but I'm just trying to understand what happened and why.

Thanks in advance!

 

[rdd1952]

Your water chnge would have removed most of your nitrite. If you were at .25ppm and replaced 80% of the water with fresh, nitrite-free water, then your nitrite reading should have gone to .05 or a level that you wouldn't be able to detect with a regular test kit. The nitrite will return as soon as some ammonia is processed. Before the water change, you had basically gone 2 full weeks without the ammonia dropping from 4ppm to 0 yet and had basically stalled at about 2 ppm. Give it a couple days or so to get going again. It shouldn't take long.

 

[cryslea]

Okay thanks. I figured I'd removed the nitrites with the water change... I think I just misunderstand the connection between the bacteria in the filter and the results I get on the test kit. But of course you're right: the nitrite won't show up until it's eaten some ammonia. I didn't factor that in.

Sigh. Just when I think I've got it figured it...

 

[Thirdfloor]

(good grief, fish-keeping is an exercise in patience!)

Truer words have never been uttered.

I am not, by nature, a patient person, so it's been a good exercise for me as well!