Local water, TDS and you.

Debbie64 · #1 07/13/2006, 04:42 PM

I don't know what your water quality is like, but according to what I've learned from Walter at Air,Water Ice, the TDS in my local tap is on the very high edge of the scale compared to other areas in the US. I'm at about 575.

Of course I use an RO/DI - I actually have 2 - 1 inside for top off which gets prefiltered somewhat by the water softener and one outside which is the workhorse that makes large quantities for water changes.

Here's my problem: The very high TDS is eating my filters. Sediment filter is yellow as soon as I change it. I just changed my RO membrane, but that is still eating up my DI resin at astronomical rates. DI should last months, not hours, dontcha think?

Anyway, I'm considering the idea of having Culligan or Rainwater put in a unit of some kind for the outside to prefilter the water before it ever gets to my RO unit. Does anyone do that, and if so what mechanism do you use?

Any help or ideas would be appreciated!

Debbie

xinumaster · #2 07/13/2006, 06:45 PM

berryessa/680 in san jose TDS is between 210-240ppm

Unresistible Blue · #3 07/14/2006, 05:36 AM

Debbie - to help you trouble shoot the system and the life span of the filters, can your tell me what the post RO tds is, and then the post DI tds?

What is your water pressure?

Do you have chloramines in your tap water?

Debbie64 · #4 07/14/2006, 12:05 PM

xinumaster, that's the difference I guess between city water and country water which is what I've got here, though it's not well water. I'm wondering if the Salinas city water is closer to your readings, too. Hmm.

So, let's see. Post RO after a brand new FilmTec 75 gpd membrane was installed is 029 ppm.

Of course the post DI is 000. It's color changing and actually, it just hit 001 yesterday after I made about 10 gal so I need to change it before I make any more.

I don't have a chloramine test, but the chlorine content is at, hmm that's between 1.5 and 2.0. It's pretty pink.

I need to switch out my carbon blocks, also - I've got them on order now. The first one is pretty new but it's a 5 micron. The second is several months old. My filter array is 1 micron sediment, 5 micron carbon block, 1 micron carbon block, 75 gpd filmtec (98% rejection) and vertical DI.

Water pressure is about 70 - 75 psi.

Thanks for the help, Blue!

Unresistible Blue · #5 07/17/2006, 05:22 PM

So you're getting about a 95% rejection rate out of your membrane - thats pretty good.

The difference between 0 and 1 ppm (post DI) is really meaningless - you are likely at the limits of the sensitiveity of your tds meter, and the margin of error on your meter would swamp the 1 ppm difference. I'd wait to change the DI resin.