I'm trying to do a fishless cycle on a 20 gallon tank, and it is completely stuck. My ammonia is down to 0 and has been that way for about 3 weeks, but the nitrites are staying distressingly high. They soared up to over 5ppm and have stayed that way. I was adding ammonia to the tank, but gave it up about two weeks ago to try to get the nitrite down. Now I just add tap water with changes, as my tap has chloramines, and gives me ammonia after treating with Prime. I've finally got the nitrites below 1.0 through water changes, but they are not budging any lower.

My big problem is my tap water, which can have nitrites from 0.5 to 2.0. Half the time, if I want to change the water, I end up increasing the nitrites instead of lowering them!

My poor comet it languishing in a 10 gallon tank, which fortunately has a strong cycle going, and I really want to get him into the 20 gallon! The 20 gal has two penguin 150 filters on it, and the 10 gallon has a penguin 100 and a top fin 10.

So, my latest thought is to swap one filter from each tank. Would it work to get the cycle completed? Or would I risk crashing the cycle in the 10 gallon tank?

Hello cometgirl!

Do you have nitrates at all in the tank yet? You really don't need to do water changes for a fishless cycle unless your nitrates are too high. That will mess up your KH, pH.... but anyway...

Your cycle will grow the necessary beneficial bacteria (bb's for future typing ) to accomodate your chloramine and nitrite in the water. The nitrobacter are the bb's that you're waiting for here, and they can be finicky.
Do you by any chance know what your KH is?

Since you currently have 2 filters on the 10 gallon, you should be able to take the filter media from the 100 and put it in one of the 150's - and that will give a tremendous boost to your cycling effort. With the bio-wheel, and the Top Fin 10 filter - you shouldn't do any damage to your current cycle. I don't think you'd want to swap the media from the 150 back to the 100 though, as it could be higher in ammonia and nitrates than your current cycle is established for. I would put new back in there, and it can always go into the other filter later on.

Good luck!!!!

Debbie

Debbie - How does KH affect the cycle? The KH of my tap water is super high (350+) -- will this affect my cycle? I am starting to get nitrates, but they are only 5.0. I read lots about the consequences of low KH (pH crashes, etc.), but does KH that is too high have an adverse effect as well?

P.S. If it matters, my GH is quite low. I don't remember the exact number -- I can look in my log at home if you need to know.

Acupunk, high nitrates can use up the KH in a cycling tank. That - in turn - drops your pH, and the cycle gets messed up. Well, the attempted cycle. I had that problem with my fishless cycle, so I can't say what would happen with fish in the tank.

Having a high KH isn't a problem for the cycle, only if it's too low. I have very high KH, also. Koko has a pinned thread on KH and in it she says that KH that is too high can be harmful to fish... but I don't know how to lower it. Let me see if I can find that thread for you...
pH, KH Problems, How to Fix There you go. It doesn't say how to lower the KH, though. I'll have to look into that when I get the time.

Good luck with your cycle!!

Debbie

Thanks for the reply Debbie,

I'll check the KH now, but last time I measured out of the tap, it was about 80. I have some nitrates, out of the tap they are 5, and in the tank they are almost 10 now. I also check the pH most days and it is holding steady.

I didn't think about moving just the media (picture of me slapping myself on the forhead) That's what I love about Koko's. Someone always tells gives me an idea I never would have thought of on my own!

Of course, I don't actually have the biowheel in the 100 filter because the tank is in my daughter's room, and the filter was very splashy and she couldn't sleep. I have instead filled it with ceramic noodles, a filter cartridge with the carbon taken out, and quilting floss to quiet the splashing.

Okay, I just tested the KH and it is 80. I also tested the nitrite in the 20 gal, and it is at 0.5, so hopefully things are moving along! I'll try moving over a little of the media from the 10 to the 20 tonight, and see how things go.

Due to excessive nitrite testing, I'm going to have to go buy another test kit! I squeezed the last drop out just now.

The test kits sure seem to run out fast, don't they?
A KH of 80 is okay. I don't think it's great, but it should hold fine.
The media in the filter is great! Even if you took out half of it, and put it in the 20 gallon - it would probably help.

Keep us posted!
Debbie