TDS Levels?

Just got in my new TDS meter from WCR. I tested my RO water that I buy from a local water supplier. It tested at a 10-11. Is this clean enough to put it in a back pack and start cleaning? Or would I need to get a DI setup to pass it through? I am going the back pack route for now and will eventually go full blown WFP. Have been keeping up with the Marks episodes. Any input woud greatly be appreciated.

On all the research I’ve done, I found that water spots at 10 tds. I’ve cleaned windows before with distilled water from walmart, I don’t do that anymore, because it spots. For your situation I would buy a DI set up. You can always just buy a dual canister DI set up from bulk reef supply for about 60 bucks, of course the DI canisters only measure 2.5" by 10" . but when you’re water is only 10-11 tds, these will work just fine for you. Let us know how eveything works out.

Properly distilled water should have a TDS of no more than 0-2 ppm. Unfortunately as you stated it was from Walmart so who knows about the quality.

I asked on a Faceook group what the highest TDS level could be for wfp work. Most agreed we need to be below 10 ppm but there were a couple, including Perry Tait of Future Of Cleaning Reach It products that claimed in some instances as much as 50 PPM could work. In the end it might be up to the invidual to test the limits.Me personally I don’t have time available to go back and do a reclean so Im targeting for 0ppm whenever possible.

I’ve had the Walmart distilled water here and wasn’t sure of the TDS. When I got my meter it read 5ppm so at least here it’s good to go. However I found a place that sells RO water for $.30/gallon and it’s at 5 ppm as well (compared to $.70 gal at Walmart). You may just have to poke around a little and look for a water treatment business that does this. Like a Culligans or other filtration type of store. You could probably find this in your neck of the woods. I plan on setting up a rainwater harvesting system sometime soon.

I would go with 0.

A few months ago my DI resin needed to be changed, but I didn’t have any with me and I was 45 minutes from home. I cleaned at about 15 TDS and it worked out fine for me. I did a few jobs in the 10-15 range with no problems, though it’s not what I prefer.

$.30/gallon is steep.I pay $.07/gallon for RO water. I told the water place owner to go up on his prices but he refuses. I will test it out on my own windows and see what happens before I venture out to my accounts. Thank you very much for your input. And everyone elses. Sure appreciate you taking time to reply.

The UK forums sometimes talk about getting the water they use from stores/businesses that are related to pet fish/aquarium, don’t know if anyone here has done it, and if it is cost effective.

It all depends whats in the water and youll never know until it spots… I have cleaned at 40 with not a spot in site… Other times I have been at 4 or 5 and it spotted…

Under 10 is usually a safe rule of thumb though.

good luck.


Old thread resurrected:
Yesterday I cleaned with TDS of 24. Then cleaned gutters and went back to look at the windows - no spotting. As Chris has pointed out, probably is determined by what contaminants are in the water.

What has your successful max been?

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I cleaned the windows at my house about 2 weekends ago… By the end of the job I noticed my tds jumped to 36 - the windows came out great. - I was surprised.

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Hey Everybody, I think its very dangeous to clean with a high tds. One time I had hard water spots, whitch are not easy to remove, but it was in a hard water area. An employee did not check the tds and it jumpt to 140.
But an other Question, when we clean with let me say 10 tds, and we do it 20 times on the same windows. Is it the same like to clean one time with a tds round about 200? Or I am wrong ? When we clean with a tds more than zero, there is always some lime left on the glass, or not? Or does the pure ( or almost pure) water connect with the minerals an takes them away? I don’t have a answer to this question, an thats why I never clean with more than 1 or 2 tds.

I do not believe that a 10 TDS used 20 times on a window calculates into 200. It just does not work that way. If it did I could buy 10 gallons of gas and pour it in the tank, drain out and pour again 10 more times and have 100 gallons of gas. :-/

P.S. you can also quite effectively clean with 10-15 TDS. If there is some contaminant element that is especially strong then this might be too high, but pretty sure you can get away with it and no noticeable effects.

Thank you for your answer. But I think you misunderstood me. Maybe because of my English. But I try it again. If I clean with 150 tds, i have hard water marks on the window and if i clean with tds 10 or 15 tds there is something left on the window ( hard water spots) but it is invisible. But if do it again and again, then it builts up and I have the same result like if I would clean with a very high tds. Or do I misunderstood the whole thing?

Yea, that theory doesn’t quite sound right.

I get what you saying; it seems you are suggesting that an accumulation over time of non visible contaminants would build on top of each other until they finally do become visible.

I just don’t think that it works that way. Solids filtered out is solids filtered out; they don’t all of the sudden show up like dust builds on top of dust until it is a glob.

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The age old question what tds level does not spot? Time has shown us there is no one answer to that question. Why can Chris get spot free results at 30 ppm in NJ and Joe get spots at 6ppm in Texas? Well TDS stands for total dissolved solids. Or minerals in the ground or from run off that end up in our water supply. Every region has a different type of mineral configuration in the water. Some minerals are more noticeable on transparent surfaces than other thus each region gets different results. When I am asked this question I tell them use the eye test. When you start to notice spots you can learn your water supply and what level you need to change you resin.


Depends on glass type cleaning too. Some rinse and roll of better than others

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I’ve cleaned with tap water at 100ppm and there was no spotting at all.
It depends on what type of minerals is in the water.
Different areas different minerals.
I do think it’s type of glass also.


If you are “cleaning” the windows each time you apply the 10ppm water then NO you don’t get accumulation. Remember that when you clean, whether by traditional scrubber and squeegee or WFP you are agitating the dirt so that it is removed by the squeegee or the rinse of a WFP. So therefore the glass is always back to a low residual amount of dirt or whatever.
The only time you will accumulation is from constant run-off of rain or where a sprinkler constantly hits the glass; and hard water stains will appear in these areas. You might even get blamed if you are not aware of a sprinkler!

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I’ve cleaned with 100+ TDS through an exhausted DI tank and still had perfect results…