Originally Posted by tripper
What issues are there with having a sand bed inbetween these two depths?
None really, if you have a 1Â½-2" sand bed you will still get NNR
to some degree if the sand grain is fine enough and oolitic. That combined with any LR
(the more the better) will complete the nitrogen cycle. The deeper the bed the more likely NNR
will occur without the addition of rock but it also means the types of bacteria and how they feed also change. Instead of facultative strains that release N2 and CO2
, you end up with strict anaerobes that release much much more.