Water ppm question for soil grow

I just checked my tap water with a TDS EZ TDS Meter and it read 166-170. I also tested watter from filtered water from fridge which is 137. Do I need to ph up or what. Finfding it hard to know which water is best to start with. I have ph up and ph down. Help

If you have the drops kit , there should be a color code on the little bottle , red to reddish to orange to green to dark green . One is acidic - alkaline , than there is a neutral zone for plants . You want your Ph at 6.2 right now .

TDS…total dissolved salt…amount of minerals and salts in the water
pH…a measure of acidity or alkilinity

Do you have well water? That’s what the TDS indicates. Hard water.
ph up or down won’t help that.


PPM and pH are different things. The TDS ppm reading might be ok at under 150ppm for most soil grows. It might be still high for hydro, you would need to get a R/O filter or buy distilled water so you have near zero ppms.

Most likely your tap water will have a pH of around 7.5, this is average for most tap water, more acidic and it eats away at the metal pipes, and maybe even makes plastic pipes brittle after awhile and can contribute them cracking and leaking. If the pH is a lot more alkali, similar things can go wrong, and also often you get excessive mineralization and crusting and such of water fixtures.

Either way the pH will likely need to be brought down to 6.5 for soil or 5.8 for hydro.


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Right MacG/ I( saw that too. Member is confusing PH with TDS=ppm

PH for your soil plant should be targeted at 6.5-7.0 with 6.5 being the optimum PH.

How strong to mix nutrient solution depends on the stage of your plant. What type of soil you use is also a big factor in determining the proper TDS/ppm needed for the plant.

As far as your water goes. The water from either source is OK. Your filter is not doing a very good job. When I run my 220 ppm well water through my RO filter system; I get a ppm of .357. Almost no ppm level at all. :slight_smile:


What size and type of
R/O do you have do you change filters a lot? or do they make them with permanent ones . ihave hard well H2o to say the least . but want to bump up to an R/O system soon as possible . i cant MAX out until then

C’mon Man…

Id you need a filter; You will have to always replace that filter; Sooner or later metals clog up your water filtration units, and the filters need to be replaced.

WELL i have never used one or even had one in hand ever AND while reading a little bit some mention waste water . as if their using FLUSHING FILTERS . sorry i asked…


Here is your typical Ro UNit.:
The horizontal filters on the top are self contained and are replaced individually.

The Vertical cylinders underneath contain the coarser fiber filters used to remove metals. You unscrew the cylinder and replace the filter. These filters are really inexpensive.

This is a great addition to anyone’s grow room, or water supply. It allows you to totally control what minerals and nutrients you are feeding your plants. my RO Unit decreases PPM in mt well water from 220 ppm - .337 ppm.

Well worth the investment.


Hey guys , I’ve been researching ph and ppm today and am a little confused. If anybody knows a direction to point me in I’d appreciate it ph is 7 or a little less. All the article spoke of hydro and nutes when talking ppm. Well I’m soil with a ppm of 32. Do I test the runoff? And adjust ?

I get readings in the 500s where I’m located. Just really started being a stickler with it and hoping to reap the benefits of this new r.o. system that just came today