Question about runoff ppm

So I had been high with the ppm and I have been watering with just plain pH water no nutrients for the past few watering. I even ran a semi flush (used 5 gallons of pH water in 3 gallon pots) which it brought down my ppm. That was 2 watering ago. Each time I have watered with plain pH water the ppm has gone up from where I was at the flush. Why has the ppm gone up without adding any nutrients? Just trying to understand the whole ppm. I am using fox farm forest soil. The plants look to be doing good so I am not too concerned more curious then anything. I am also 9 days into flowering if that has anything to do with it.

Thanks!! I can get specific numbers when I get home if that helps.

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What were the numbers so we can understand the scope?

If it went from 200 to 250, no worries, probably just variation in the readings. If it’s 100’s more than we can start to try and understand.

Also, what is the PPM of the water you’re giving them? Tap water I’m guessing?

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I can give you rough numbers at the moment I am at work and don’t have my notebook with me. So before flush I was about 2000 and after flush brought down to about 1000. The water I am using is about 400-500. The last 2 watering have gone up about 200 each time.

yes tap water that has been sitting for a couple days open to air.

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I would say, if you’re watering with 400-500, your plant is consuming less than that and it’s building up. I would try to maybe avoid tap water if possible because yours seems pretty high. Mine was 164ppm for example.

I started collecting rain water from my roof and that runs between 3 and 20 ppm depending on how hard it rains.


If you water with 400 PPM and your plant is only consuming 200PPM, you get an extra 200PPM each watering, after 2 it would be 400, 3 600, etc. More or less, probably not a perfect science.


There’s also nutrients (ppm) in the fox farm ocean Forest soil


Thanks @Matthew420 @Paranorman

Do you think that the amount of water used in watering has anything to do with it?

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I think as long as you have drainage it’s more a factor of putting in kinda high “base” PPM. Can you get a water report from your town/city? Could be stuff in there the plant isn’t using at all.


Can you text the phone on drain water or soil. And will the phone level be higher in soil or when draining