View Full Version : Just measured total dissolved solids

Steven Ruttenberg
5-Feb-2019, 22:07
In my water. Tap water from softener has 440 ppm, from RO 22 ppm, filters are 2 years old though. Distilled water from store is zero. So RO system is pretty good.

30-Mar-2019, 00:38
In my water. Tap water from softener has 440 ppm, from RO 22 ppm, filters are 2 years old though. Distilled water from store is zero. So RO system is pretty good.

FWIW, I'm a reefer in Vegas. (Saltwater coral aquariums. They require 0TDS water so I've got a serious RODI setup for water treatment.) Tap water from the street is ~425TDS, 1 sediment, 2x Carbon filters and a stacked set of RO membranes makes ~8TDS, then into two Deionizing resin canisters. = 0TDS.

Membranes get changed every other year. Filters get changed every 6 months. DI resin gets changed when the TDS out of the first DI chamber goes above 0.

Look on youtube for the BRS RODI videos.

Peter Collins
30-Mar-2019, 06:01
Steven, I think your RO TDS is a little high with respect to what those systems can deliver when filters are within stated capacity/throughput.

HOWEVER, 22ppm TDS is very suitable, a well-controlled water for making photographic solutions--developer, stop, fixer, toner solutions. The water quality at 22ppm TDS means that other variables, such as temp change of developer during developing, are much larger variables potentially causing variation in final results, either negative or print.

One other thing: 22ppm TDS is just fine, especially if it always remains about the same value, such that it is a constant in the equation of variables.

Have fun!

Steven Ruttenberg
3-Apr-2019, 21:02
I put a new filter in and still right at 22. It is a GE system. I think it would take me an additional system to get to 0. But as you say 22 is acceptable and it does stay constant.

3-Apr-2019, 21:07
I think if you get to zero TDS, your pipelines will be in trouble and you may get pinholes in them. Zero TDS water is very corrosive and need special plumbing. Even 22 is still hard on your pipes.

Peter Collins
4-Apr-2019, 06:01
But pepe, two comments:

1. With under-the-counter RO treatment systems, the lines are all plastic, with a coupling to the riser of the spigot. The RO units are downstream of conventional piping. But ultimately not relevant BECAUSE--
2. Zero RO (or quite close, as in 22ppm that Steven gets) should not be confused with low pH water. Acidic water, e.g., pH 2, has dissolved solids in it, depending on the kind of acidification, such as SO4, Cl, in sulfuric and hydrochloric acids. Would measure much greater TDS than zero RO water.

From he who worked too close to an environmental lab using EPA-approved procedures.

Steven Ruttenberg
4-Apr-2019, 12:06
All my plumbing as mentioned is plastic from RO to faucet. Plus I believe all plumbing in house is plastic. I will go back and look at construction photos.

4-Apr-2019, 14:34
Steve: I advise you do some more research in your own. Plastic has its own problems too. Have you heard about nanoparticles? Do some more research.

From he who did not work in or too close to an environmental lab, but who helped write the plumbing code. ;)

Peter Collins
4-Apr-2019, 17:02
Wow, pepe!

Steven Ruttenberg
5-Apr-2019, 14:37
Well, not much I can do about plumbing. But in AZ they have to be pretty good with it because our water is hard as a rock. I have heard of the nano stuff, but haven't researched it. Since my system is between sink and and supply line, worst I would have to replace is a faucet. I do want to put something in line and get a higher capacity system with a large storage tank.

5-Apr-2019, 16:23
I get 500mg/l TDS and sometimes more and do the washing with it. For mixing the chemistry, I used Distilled Water from Walmart ($0.99/gallon). Sometimes, I just use water from the refrigerator, which has been filtered a little bit. I have no problems with the water at all.