ive got 400kg of lytag filter media to go in my tropical pond and was wondering if using it as a substrate would be just as effiecent as it would in my sump.my reason for this would be to then run more moving bed media in the sump. the tank is 15000litres.and sump is 1500mm by 1000mmby 1200mm deep. running as a river theme from one end to the other with a turn over of 40000litres an hour.
