Originally Posted by good11s
OK help me out. My tank has been set up for about two months and Fallow. I cycled the tank with a raw shrimp from the store. The tank was going great with lots of pod growth
Last week my parameters were solid: NH3
=5-10ppm, PO=0. Then all of a sudden last night I have a NH3
spike and my NO3
are 0. What the heck?
The only thing that has changed was I added new PC
bulbs. I have a pretty good datom bloom in my fuge and even in the tank, and some good alge growth on my rocks. I can figure out what is happening.
I am concerned since I have inverts arriving tomorrow.
75 gallon with 130lb LR
. 3-4" (80lb+) LS
40G sump with LR
rubble, and fuge with Cheato and a DSB
Were you "feeding" your tank while it was fallow? In other words, were you supplying it with an ammonia source such as fish food, etc?
The original cycle established the beneficial bacteria, but for them to survive they need a source of ammonia. Normally, this is supplied by fish waste, respiration, excess food, etc. But in a fallow tank, you need to somehow get them the ammonia they need.
If you weren't feeding the tank, you could be seeing a die off of the bacteria. I believe it was in Fenner's book that he mentions that folks would be surprised at the bioload from just their bacteria, and that a bacterial die off can foul a tank just as much as a critter dieing.
The nitrates going to zero from 5-10 could also be your semi-deep sand bed doing its job of converting nitrates to nitrogen gas.