I’m still in process of setting up so not sure how well this is going to work, but I am setting up with a perforated plate supported 1 inch above bottom of tank. Substrate will be spread across top of it. Closed loop pulls from back wall of tank and returns water up through bottom of tank into this under-substrate chamber. Water will flow up through substrate to lift detritus up and into water column, to be removed by filters in sump (pair of ClariSea automatic roller filters).





To use bleach in or near a biological system - is only a big NO-NO for me. Bleach can form chlorinated organic products that both are bioavailable and bioaccumulative. If you aim to kill everything - use H2O2 - it will not form any harmful residues - only water, oxidized products and oxygen - it will only kill present generation - not the next



