I think you want to be aiming towards
at least 1lb
live rock/gallon water, if not more. This will help to significantly increase your denitrifying bacterial population.
Is your sand super fine or coral sand? The reason I'm asking is because larger grains of sand will only serve to trap
detritus if not stirred up frequently and will ultimately result in high
nitrate levels.
For a deep sand bed (DSB), you should be aiming at a minimum of 4" of super fine sand (preferably
aragonite-based).
DSBs are super at reducing
nitrate levels (well, rather the bacteria residing in them!) :-)
How long has your tank been up and running?
