When I first started reading up on growing, every video and article I read suggested RO water systems, if your water had a high TDS. But sadly I can’t remember what the actual readings which were said to be too high, and thus an RO system was suggested.I picked up a seems to be a decent Milwaukee meter and tested water I have here, which had been in my fridge for the last day or so, and it gives a reading of 90 ppm.
Is this low enough that a RO system wouldn’t really be required for a grow, or would you still recommend I install one? Ironically I expected the reading to be much higher, because although I rarely notice any unusual taste to our water, well except during extremely hot summers if an algae bloom causes the water plant to increase the amount of chlorine they add, but my wife always complained, so I got her one of those counter gallon water distillers, although since that requires 5-6 hours per gallon, and then time for the water to cool, it wouldn’t really be practical to use for anything beyond the seedling stage.
If you still would suggest a RO system, could you also please suggest, if not a specific model, at least a type, or what sort of filters it should include, as I’ve done a bit of looking at various ones on Amazon, but they seem to vary on number of filters, I’ve seen from 4 to 8, and from something like 60gpd to several hundred gallons a day (I assume the smaller volume ones are to hook up under a sink, and the hundreds of gallons a day ones are for hooking into the main line, to provide RO water to the entire house?)
1 Like
So at first I went down this rabbit hole myself.
I was convinced I needed RO or at the least distilled or super filtered water…
I was spending $1 a gallon buying it and then trying to deal with 100s of plastic jugs 
It was a disaster 
trying keep up with 12 plants…
So i started using my tap water (ppm 50-125) after letting it set out to get rid of chlorine on 2 plants…
Saw absolutely no difference, after a month I started using my tap water exclusively and have had no difference whatsoever…
RO water is expensive to produce and it waist so more water then it gives you clean “RO” water…
In my opinion, it isn’t worth it unless you jyst got money to spend 
3 Likes
Awesome, thanks.
I’ve seen other mention it wasting water as well, and while I’m familiar with what RO is, I’m not sure how it works in these systems. So are you saying that it doesn’t just hook to the water line, and use the filters to pull out the water for the RO reserve tank, passing the rest on through, and instead runs in it’s own loop, thus any water that doesn’t pass through the membrane just continues out into a drain?
2 Likes
I’m not exactly sure how but yeah it produces waist water that must be drained away…
1 Like
Ridiculous amounts of water sometimes.
1 Like
When looking at ro systems, you want a one to one ratio…
Meaning , for every gallon of good water it dumps a gallon of dirty water …
Best ratio you will find…
And I would only recommend ro water if your only growing in water , no media…
I’m a water only grower , so my water has to be as pure as possible so I don’t run into any issues…
Soil and coco can fluctuate with no issues with a starting ppm of less than a 100 ppm…
I run my water at less than 5 ppm and a ph of 5.5 in flower and a starting point of less than 200 ppm and a ph of 8 from my well water in vegg with no issues…
Hope that helps…
I run a six stage ro system with a 100 gallons on hand at all times of ro water…
4 Likes
When I lived in SoCal the town water supply delivered 550 ppm at the tap. If doing any kind of media grow or hydro you have to account for the existing TDS when mixing nutes. This means that if you had a target of 900 ppm in Jack’s, starting with a base of 550 ppm you can only add 350 ppm of nutes to get to your target. Way less than ideal when growing hydro for example.
I’m in Colorado now and the TDS at the tap is 130 ppm which is heavenly compared to where I came from. No chloramines so I can live with that value in my grow here. If your muni water supply uses chloramines you will need to find some way of removing it.
Like the 'Fuzz said; a good R/O system will waste 1 gallon of water for every gallon purified. I had a cheap unit (R/O Buddy) that was more like 3 to 1 but got the job done.
4 Likes
