AquaPro Compact R.O. System. the use of 3 particularly effective membranes, the system does not use a storage tank . This saves a lot of space in the kitchen cabinet. AquaPro reverse osmosis system AquaPro AQB-600DF also contains a post-cartridge AIC-2 with activated carbon. Thanks to the use of highly efficient membranes, the filter produces clean water without the need to accumulate it in the tank.