RO unit questions

I own both a 90gpd "generic" RODI unit and a Spectrapure 90GPD MaxCap DI system....

NIGHT AND DAY.

The generic has lame little DI piggy back horizontal canisters that are hard to refill, and most of the water passes over the DI, not through it. I can see the top of DI bed change color and exhaust in a few days of use, while the bottom won't change color for months so I can only assume no flow, no exchange.

Spectrapure's MaxCap system gives even rates of exhaustion in the DI canisters, which are full sized, and easy to refill or replace (in the case of the silica buster cart)

My generic RODI unit that's rated for 90gpd produces about 70 gal / 24hours with a decent GE membrane. I get closer to a 5 to 1 rejection rate, which IMO is just a waste of water. My pressure is right at 80psi. The generic filter system also doesn't account for or allow any adjustment of the flow rate of the rejection line, which can affect the lifespan and rejection rate of the membrane.

the Spectrapure not only has the little capillary line in the rejection tube, but included concise instruction on how to manage rejection and what to look for. I was able to tune my rejection rate to 4:1 as per the instructions, and the membrane produces just a bit over 90gpd if my math was right. I will know for sure when I go to fill my 180g tank, it should take it just under 48 hours if I account for displacement from rocks and sand + sump capacity.

Also, the Spectrapure has 4 point TDS monitoring, the generic has no monitoring.

SpectraPure came with extra hardware and instructions in English
generic came with no instructions and a CD with a copy of a website in Polish or Russian or something, circa 1995 that had pics of a different unit.

Well worth the extra $200 or so I spent on it.

-Doug

p.s. I don't work for SpectraPure or anything, but they have a GREAT product and even better service, like when it came the pressure gauge was smashed, and they replaced it no questions asked, shipped priority took 2 days to get to me, and offered me 20% off my next membrane purchase, which I haven't needed to place that order yet)