zeroinverse
New member
A deep sad bed of 5+ inches deep will create anoxic regions (low to zero oxygen areas) for denitrifying bacteria.
One of the by-products of one type of denitrification generates hydrogen sulphites/sulphites (I forget which).
It is that rotten egg smell. In tanks, DSB are usually slowly stirred up by sand sifters critters that help release trapped nitrogen gas and the sulphur compounds back into the water stream. Once released, the sulphur eventually out gasses out of the water.
When you mix up a sandbed, too much sulphur gets released too fast.
That is my guess why you had the crash.
One of the by-products of one type of denitrification generates hydrogen sulphites/sulphites (I forget which).
It is that rotten egg smell. In tanks, DSB are usually slowly stirred up by sand sifters critters that help release trapped nitrogen gas and the sulphur compounds back into the water stream. Once released, the sulphur eventually out gasses out of the water.
When you mix up a sandbed, too much sulphur gets released too fast.
That is my guess why you had the crash.