RO/DI - Time to Replace my Filters?

[Snowboarda42]

Hey everyone,

I have a 5 Stage, 100GPD RO/DI filter. The steps are as follows:
In, 5 Micron Polypropylene, CTO GAC, 1 Micron Coconut Carbon Block, RO, DI, GAC, Out.

I finally got a TDS meter, and I have found the following.

Water in 57-60PPM
Final Water Out - 0ppm

Water Out After RO but Before DI - 0ppm
Water out from First 3 stages, before RO and DI - 60ppm

So it looks like my first 3 steps (5 Micron Polypropylene, CTO GAC Carbon, 1 Micron Coconut Carbon Block) aren't catching whatever is in my water. Should I go ahead and replace them?

 

[DonW]

The prefilters are not going to remove dissolved solids only actual solids. Use a pressure gage to check the pre filters. Also recalibrate your tds meter. In a perfect world with a 98% membrane your ro output should be about 1.5 and since we know the system cant be running to perfection it should be even a little higher.

Don

 

[Snowboarda42]

Will do, Don.

I just bought the TDS meter, I'll order up some TDS solution and a gauge.