Nitrites to Nitrates

[richardh]

I have been running 2 tanks side by side for some 4 months now, 33g and 17g. I cannot seem to get get the 17g cycled. I always have nitrite show up after 4-5 days. I have even moved the much larger filter from the 33g to the 17g, this has made no difference. Incidentally the 33g is still doing fine with the smaller filter!

I should add both are lightly stocked with fish. I have even tried moving almost all fish out of the smaller tank, still Nitrites show up. Tap water has none btw. Never had a problem with ammonia.

Only difference I can see is that I have a small air stone in the 33g and sand rather than gravel. Could the additional oxygenation be converting nitrite to nitrate?

[jlk]

Is there a difference in ph between the 2 tanks? Or is the ph crashing in the smaller tank? What type of sand is in the 33g?

[richardh]

Originally Posted by jlk

Is there a difference in ph between the 2 tanks? Or is the ph crashing in the smaller tank? What type of sand is in the 33g?

Ph is stable in both tanks at 7.4, never seen a ph crash in either tanks. 33g has sand bought from pets at home, not sure what type it is but very fine. 17g has black pea sized smooth gravel also from the lfs.

[jlk]

Hmm...you have me a bit stumped here. This tank really should be cycled as long as its not overstocked or overfed & the ph is remaining stable. It cant hurt to add some additional aeration to the 17g in the meantime. Since my ph theory has been debunked, hopefully, someone else will have an idea of why this occuring!

[librarygirl]

Hm, so the 17 has been up for 4 months with fish? Should definitely be cycled by now. Are you adding dechlorinator prior to water changes? The extra aeration is good for the bacteria but unless the 17 gal has no water movement at all I wouldn't think the lack of an air stone would be a big issue. What temp is the tank? The PH is stable so that's not the cause either. You're using regular tap water, right? Is there any chance something could have gotten into the tank, such as bleach or antibacterial soaps or anything?

[richardh]

Originally Posted by librarygirl

Hm, so the 17 has been up for 4 months with fish? Should definitely be cycled by now. Are you adding dechlorinator prior to water changes? The extra aeration is good for the bacteria but unless the 17 gal has no water movement at all I wouldn't think the lack of an air stone would be a big issue. What temp is the tank? The PH is stable so that's not the cause either. You're using regular tap water, right? Is there any chance something could have gotten into the tank, such as bleach or antibacterial soaps or anything?

17g was set up as a fish in cycle-my 1st ever tank. 33g was seeded from the 17g and has never seen a massive spike of any kind. Temperature of both tanks are 25C. I always use dechlorinator during water changes and use tapwater, which is soft in my area. I am always careful not to introduce soaps etc.

I'm at the point where I have to get rid of the 33g anyway, as I don't have space for it. The way I feel right now, the 17g might go as well I just don't understand, ammonia is 0 and has been for months. Can't get rid of nitrite and always show up after 4-5 days. Nitrate readings are always low, up to 10 ppm.

[librarygirl]

So you pulled media from the 17 to cycle the 33? How long ago was this? What filter do you have on the 17 gal and what fish are in there? The only other thing I can think of is if there's not enough surface area for the bacteria to grow to accomodate the stock in the tank, but unless you have a very small filter with not much media and a lot of fish then this might not be an issue, but it's just one I want to check.

Also what test kit are you using? Have you checked the dates, maybe it expired?

[richardh]

Originally Posted by librarygirl

So you pulled media from the 17 to cycle the 33? How long ago was this? What filter do you have on the 17 gal and what fish are in there? The only other thing I can think of is if there's not enough surface area for the bacteria to grow to accomodate the stock in the tank, but unless you have a very small filter with not much media and a lot of fish then this might not be an issue, but it's just one I want to check.

Also what test kit are you using? Have you checked the dates, maybe it expired?

I squeezed one of the sponges into the 33g some 3 months ago, that was enough to seed it. 17g Filter is an aqua one 102, suitable for up to 20g.

As of today, stock in the 17g is:

1 dwarf gourami
3 oto
3 guppy
1 platy
2 Pygmy cory
Shrimp and snails

I have removed 5 cardinal and 5 harlequins today to bring the stocking level down. Perhaps I was a little over stocked. I have also moved the airstone into the 17g. I will see what the next week brings. Api master is my test kit and in date.