How important is tap water quality in a DWC?

[JohnC]

Hi folks,

I am considering going with a DWC setup (including top feed) on my next grow. I'm concerned about the water to use in the reservoir.

I've only got a half-dozen soil grows under my belt so I certainly still have a lot to learn.

My local tap water (Colorado Springs) has a very high PH (~8.3) and tastes literally like pool water. So in my last two grows, I decided to use distilled water instead of tap water. A pricey decision to be sure but I found it gave me better control over nutrient levels, I didn't worry about other minerals / chemicals already in the water, and I've had less problems as a result.

Other than adjusting PH and careful measured does of nutrients (I plan on starting at 1/4 strength), will I be safe using tap water in my reservoir? In other words, how likely am I to encounter problems resulting from all of the "other stuff" that's in my tap water other than any nutrients I add?

I know monitoring your water in a DWC environment is extremely important. I'm just worried about challenges resulting from using my tap water.

Any advice?

[dontknownuttin]

Think 5 stage Reverse Osmoses

[Weed Pharma]

Just take a look at the water quality report from the water company. It will provide what is actually in the water, in order to determine it's suitability.
check the ppm's also. I worried about my water and tried alternate sources until I found out the ppm was @ 38.

[JohnC]

I read, or should I say, tried to read my water quality report (attached) but honestly I couldn't understand the majority of it. I guess that's another reason why I gravitated to distilled water; I didn't worry about such stuff.

I suppose I could at least start out using it and see how I go (or grow, as it where). If I run into troubles that I cant attribute to my screw-ups, I can always switch back to distilled, right?

In the mean time, I certainly will look into a RO system.

[Weed Pharma]

Well the ppm's in the report is high @ 500 if I am reading it correctly- depending on how many plants you have, you may want to use a Zero Water system, https://www.target.com/p/zerowater-2...Q&gclsrc=aw.ds

[ellz]

If PH is the only worry, then you can just control that with some PH up/down solution. I live in Grand Junction, and our tap water has a PH of about 7.5 and I used the General Hydroponics PH Down to get my water down to a PH of 6. It's not the easiest thing to do at first, but once you know how much per gallon to add, it makes it easier. As for your PPM, that is only important from what I have seen if the PPM is very high. I tested that theory on the General Hydroponics website under the custom feeding schedule maker. I started with a PPM of 700 (which would be poor quality tap water) and then tried the same schedule with a PPM of 200 (average tap water) and both came back exactly the same as far as amounts of nutrients to add so I am not seeing that being a big issue. I know there are growers that worry about EC, PPM, PH, Temps, etc...but the most important two things I have seen that really matter are PH and the overall water temperature. Oh, and as far as a RO system...if you use one, be sure to replace the calcium and magnesium that the RO system removes! Some Cal-Mag would be a good buy. More info on RO can be found here.
Hope that helps.

[JohnC]

Excellent info. Thanks!

[Sammy]

My water comes out of a green garden hose pH usually Winter time about 6.2 summer they bump it up to about 7.3 7.5 don't know why it very so much. PPM hits 44 Max never had a problem living in the south.

[gbauto]

Based on that report I'd say just let the water 'air out' until the chlorine evaps and then adjust pH to get it where you need it. You have a fair amount of dissolved solids so take that into consideration when monitoring nutrients in solution. I don't think that you'll have any real challenges.

[alltatup]

JohnC, since your tap water won't be the same as mine, which comes out of the faucet around 6 pH, I think you will have to experiment.

I don't have a problem with mine, but you may have a problem with yours; it will be interesting to see if you can get and keep the pH down. Otherwise, I agree with DKN about getting an RO system that can be moved (doesn't have to be installed under sink).

[oldjarhead100]

I personally don't like ro systems they waste more water than you use but alot of growers love them . I installed a whole house filter on my garden supply line I change the filter every couple of months takes care of chlorine and dissolved solids just one more idea

[alltatup]

True about the wasted water...

[POKEDSMOT]

Been having good luck with getting water out of the machine. $1.25 a week isn't bad.

[dontknownuttin]

I run the waste water line out to my citrus trees they love the water! The filter provides me chemical free low TDS water.

[oldjarhead100]

great Idea about the waste water DKN

[dontknownuttin]

My plants love R.O. Water!!

[oldjarhead100]

don't get me wrong RO is the best but I just cant waste all that water you have found a solution for your waste I applaud that DKN

[dontknownuttin]

Out side FULL GROWN Citrus trees like lots of water and here in the desert who wouldn't?. All I know is my home city tap water has a TDS of 172. After running this water through a 5 stage filter, it comes our at a TDS reading of (2) TWO!. 172 TDS city water is not bad just a little hard. The "Brine" or R.O. waist is just fed to my big trees they don't seem to mind. WOW! the outside temp. here is expected to reach 115!. Good thing my plant has A.C. like Mother Nature intended 72 at canopy level RH 24%. The R.O. filter has caused my water bill here at the house to rise $3.00 THREE DOLLARS!. I then remember paying for jugs of clean water at my local store and paying .95 a gal. (this gets old). My estimated cost for water now is 4.2 cents a gallon! AND I DONT HAVE TO DRIVE TO THE STORE (another cost to think about.) The filter has a average life of 500 gallons (or so they claim), After it is used up replacement filter cartridges are available. I test EVERY gallon I produce as I produce it (better safe then sorry.)

[alltatup]

You are taking excellent care of your plants.

[D.A.A.S.69]

Those are some tough ass citrus trees to continue to take those high temps like that year after year, do they produce good fruit ? That Stage 5 is doing a good job by giving the dregs to the citrus trees.

[dontknownuttin]

I learned a lot here so far from Green! (the check is in the mail LOL). The lines running from the filter itself PERFICTLY fit my home irrigation system. I simply plug the R.O. waste line into my homes irrigation manifold during manufacture of clean water and send that high TDS waste water anywhere I choose in my yard.