PDA

View Full Version : rejection rate


garyw68
02/02/2010, 08:11 PM
what does the rejection rate mean when looking at RO membrane? im looking at the 75gpd which has 98% RR while the 100 has 90% RR.

thanks

Thefilterguys
02/04/2010, 09:55 AM
The veried rejection rates are for total disolved solids. 75 GPD membranes perform far better then 100 GPD membranes due to the 98% rejection rate as opposed to the 90% rate. Where it makes a difference is in your DI exhaustion rate. A full sized DI cartridge will absorb 5100 ppm of tds and if your tap water is 100 tds before filtration 98% will give you 2550 gallons of ultra pure water and 90% will only give you 510 gallons of ultra pure water from the same cartridge. We are after zero tds ultra pure water because our salt mixture should provide everything needed for our saltwater aquarium use. For topoff nothing has been removed from the minerals in your tank and nothing is being put back in by ultra pure tds water topoff.

Jim

garyw68
02/04/2010, 04:37 PM
thanks jim