I have the Typhoon III
unit. It uses a Filmtec membrane. I connect it when needed via a garden hose adpater to my kitchen faucet. I use it once or twice a month. It has a membrane flush valve that just runs water past the membrane to help clean it. I flush the membrane for a mniute or two before and after each use. When done I allow the pressure to drop back to zero before removing any lines. Usually the water level in the sediment cartridge falls a bit. I then store the unit till the next time I need it. I've been doing this for 4 years and still get ZERO TDS
(as long as the DI
lasts). My tap water still reads 185-220 tds
and my RO
water still reads at less than 12.
I don't think the membrane ever really dries out between use when used in this way.
As for quantitiy...I'm ready to get a booster pump. My tap water usually is around 40 -45 psi. The recommended parameters are a psi of 50 at a temp of 77 degrees.
They have a new 150gpd membrane that I am going to order. It specs at 150 gpd at 65 psi and has a 98% TDS
"Membranes are rated at 77 degrees temperature and 50 PSI.
For every pound of pressure less than 50 subtract 2% of the output. Example 40 PSI subtract 20% of the 75 for 60GPD
For every degree below (77) you lose production. Subtract 1.4% per degree lower than 77. Example 57 degree water is 20 degrees less than optimum. 20 x 1.25 = 25% less production. So a fifty GPD membrane will only produce 75% or about 37 gallons
Combine the pressure and temperature answers together and subtract them from your membrane rating. Your membrane should produce water at or very near that answer"