All systems are zero water exchange, meaning I don't exchange any water in any system and only recirculate it through different treatment processes. I don't use pure oxygen, ozone or complex filters as they are expensive and break too often. The commercial design of systems is always large due to a necessity of achieving the proper economy of scale to earn a large profit. Complex bio models are used to feed as this is the most important variable that must have precision and accuracy to reach the high biomass per unit volume that all my systems are capable of achieving.