Watermaker - Water Softening Cartridges and back pressure

[DevoDave]

I'm just finishing the installation of an AquaMaax watermaker.

1.0HP 12V DC motor, General Pumps WM1615 pump (1.6GPM), 5 micron and 20 micron 10" prefilters, DOW Filmtec SW30 membrane. Carbon block in a 10" housing for freshwater flush.

My issue is that they supplied a Applied Membranes water softening cartridge (10") as well, which sits in the product line. Blowing mouth-air down the product line through this cart, significant pressure is needed. I would assume water would be even harder to push through.

AquaMaax say they don't know if this is a problem, telling me to give it a go, but the manual and reading online suggests that the product line should never be obstructed..

I don't want to harm my RO membrane, so can any experts here suggest if this is a problem?

[SV THIRD DAY]

We all know the folks at ElectroMaax are far from water maker experts, so their "try it and find out" answer isn't surprising.

As long as the back pressure caused by your softening cartridge doesn't cause the product water pressure to reach the bursting point of the low pressure tubing and fittings the only real risk you have is decreasing your product water output and putting extra Amps on your 1.0Hp DC motor, which by the way is already over the safe full load amps rating. (they know this and have had several of the 1.0Hp motors overheat and burn up but keep selling it anyway and without any thermal protection...CRAZY...but it's ElectroMaax...that's the way they do things. So as a safety precaution, you need to measure the Amps of the 1.0Hp motor and compare that to your pressure gauge, then do not exceed the PSI rating when you Max out the safe full load amps of the motor, usually less than 800psi.

The real question is why do you want to use that cartridge in the first place?
They are sold and marketed for fresh water RO where the TDS is down to low single digits, but you don't really need those in sea water RO where the TDS is around 120ppm at the low end. It's a sales gimmick more than a needed item in my opinion.