Why is ther so much RO/DI Waste water

I am new to the marine aquarium Hobie and I do not understand why there is so much wast in the RO/DI filters. Is it because the water pressure is faster than the filter can process. I cant imagine why else there would be so much water waste.

Any help in explaining this matter to be would be greatly appreciated.

 

The RO stands for Reverse Osmosis and refers to the chemical/mechanical method of filtering the water. Basically the water is forced through a semi-permeable membrane that allows water molecules through, but blocks most other organic and inorganic materials. This can only happen with a pressure differential from one side of the membrane to another. But the membrane is very delicate and would burst if presented with the normall pressures a normal filter cartridge endures. Thus the water flows across the membrane with only a moderate differential pressure. The second reason for the waste water is that since the pores in the membrane are very small, they clog easily. The flowing water across the membrane also flushes the membrane clean. Even so, most RO units have a method of flushing the membrane with full flow to clean it further.

It is not uncommon to have about 2/3 waste to 1/3 purified water in a RO system.

Mike

 

A 4:1 waste to permeate ratio is the standard recomendation for systems used in this hobby.

Russ @BFS