How many days until measurable ammonia

[outflying]

Hello,

I was wondering how many days it would take to get ammonia readings. The LFS recommended 20 minnows for my 135 gallon to get the cycle started. Although he only charged me for 20 there must be at least 35 in the tank. It’s hard to count them because they are so active. They have been in the tank since last Wednesday (5 full days). My test kit came in the mail today so it’s the first time I’ve been able to test the water. I have an ammonia reading of zero.

Shouldn’t I have some ammonia by now?
Especially with so many minnows?

Thanks.

 

[TomK2]

If you are lucky, the ammonia reading will stay zero, yet you will end up with nitrate appearing in about 7 weeks. You can cycle with a low bioload, have undetectable ammonia and nitrate, yet still establish a biofilter bacterial colony. The secret is to have few fish and go slow. YOu can read more at:

http://home.wowway.com/~tomstank/index_files/page0017.htm

The basic idea is to have the ammonia generated by the fish peak below the 0.25 ppm lower limit of your test, same for nitrite, then "miraculously" see nitrate in 45 days or so. Thus, your fish are spared the exposure to ammonia and nitrite.

So, to answer your question, it depends on the bio-load of the tank. Most see ammonia within 3 to 5 days if the tank has too many fish in it. If you don't, think about letting the biofilter develope over time without a toxin peak instead of adding more fish or food.