Where Are The Nitrates Coming From?

[jsl]

Hi,
I have had tropical freshwater tanks before and the cycle has alwasy been as expected. I am setting up a new tank (after a break of fish keeping for a few years) and I'm puzzled by the water chemistry.

The tank is about 32 US Galls. Filled with tapwater after treatment for chlorine/chloramine. Tap water test indicates, ph=7.6, NH3/NH4=0.0, NO2=0.0 NO3=0.0 I have no record of hardness.

The tank has been setup with a Fluval 205 filter.

I have added some filter material from a friends established tank. 5 tetras have been added.

The chemistry seemed to be heading the right way,over a few days NH3/NH4 rose to 1.0 mg/L, nitites were nil but I noticed that nitrates had gone up to between 5-10mg/L. Right now the NH3/NH4 is still at 1.0 mg/L, I don't appear to have any NO2 and NO3 is up at 20+ mg/L.

I did a water change, 20% lst night and the NO3 dropped down a bit but its back up again this afternoon with the other parameters the same....??? Where are these nitrates coming from?

I suspect that the established filter material has the bacteria to convert NO2 -> NO3 but only a limited amount of bacteria that can do NH3/NH4 -> NO2. Therefore, the NH3/NH4 isn't rising and the NO2 level says at zero....

Any thoughts - am I thinking the right way or is something else going on?

 

[riverman444]

I think you hit it on the head. Only thing I can think of is that the filter you added from the friends tank jumpstarted your cycle. I would keep up on the water changes. Keep an eye on the Nitrite, too.

==bump==

 

[jsl]

I think you hit it on the head. Only thing I can think of is that the filter you added from the friends tank jumpstarted your cycle. I would keep up on the water changes. Keep an eye on the Nitrite, too.

==bump==

Cheers Riverman,

Thanks for your reply, I really just needed to see if anyone else thought the same as me or if I had gone crazy!

Last night the NH3/NH4 has dropped to 0.5 mgL, nitrites still at 0 and after another water change the NO3 is now only 10mg/L so it still seems to be heading in the right direction, although no more fish will be added till that pesky NH3/NH4 hits 0.0!

I'm monitoring everyday so if anything drastic happens I should catch it early enough to stop it getting out-of-hand.