cycling question # 1,000,001...

[NowherMan6]

i know the cycling thing has been done to death, but here goes:

ive been cycling a new tank for about 2 weeks now and there hasnt been a significant ammonia spike yet. i have 11 tiger barbs in a 46 gallon tank. when i test the water it shows traces of ammonia, but nothing significant. testing also shows "no detectable" nitrite. is there something wrong with this picture? should things be moving faster or is this semi-normal? they're little barbs so i know it would take a lot of waste from them to dirty up the tank, but i dont want to add new fish because eventually i only want to have the barbs and a few yo-yo loaches or a school of corys, two types of fish that dont react well to new tanks. any advice?

 

[phanmc]

Cycling a tank can take over 6 weeks, so it looks normal since you do have a god size tank.

You haven't done any water changes yet, have you? Doing water changes before the ammonia spike will push back the cycling process as it will remove the ammonia and lessen the foodsource for the bacteria. Water changes should be done only if ammonia or nitrite reach dangerous levels, or when Nitrates are detected.

 

[NowherMan6]

come to think of it, yes i did do one water change, probably 15-20% i did it because the driftwood had given the water a bit of a brownish tint. oh bother. i guess it'll just take a bit longer then...

 

[anonapersona]

wet wood?

Was this driftwood under water recently? If so, it may have brought a significant amount of bacteria into the tank, speeding the cycle. Any other sources of bacteria -- old gravel, used filter, used decorations?

There is some evidence that materials that had been covered with nitrifying bacteria may be able to regenerate the bacteria rather quickly. (Based on some experiments done by myself and some folks at SimplyDiscus forum) If old material was dried but not sterilized, it may have brought in the very bacteria you are looking for.

Or, your tests are old.

 

[JSchmidt]

Originally posted by phanmc
Water changes should be done only if ammonia or nitrite reach dangerous levels, or when Nitrates are detected.

I'd strongly take issue with this statement. When cycling with fish, any detectable ammonia means there is more than the existing biofilter can process, and the biofilter will slowly grow to meet the demand. The bacteria won't grow any faster if there is 5 ppm excess ammonia than if there is .5 ppm ammonia. Therefore, to avoid poisoning your fish, water changes can be carried out as soon as there is detectable ammonia. You should never allow ammonia or nitrites to exceed .5 ppm if there are fish in the tank.

Good luck,
Jim

 

[NowherMan6]

ok then, youre saying that doing water changes wont stunt the cycling process? and once the tank cycles with these fish, how can i prevent a mini-cycle from happening with less hardy fish?

 

[JSchmidt]

Water changes won't slow the cycle. Even if they did, which would you prefer: adding a week to the cycle or intentionally subjecting your fish to gill burns from ammonia?

The tank's biofilter will grow to meet the available food (ammonia). If you add fish, especially quite a few, you'll exceed the biofilter's ability to process the additional ammonia output and you'll have the so-called 'mini-cycle.' If you add additional fish slowly, the existing bacteria will be able to mostly (or completely) handle the additional ammonia and you won't see a spike.

All of this is good reason to consider fishless cycling next time; you don't have to worry about keeping ammonia & nitrites at low levels and you can stock with a full complement of fish right off the bat.

Good luck,
Jim