RO Water and PH

Hi RIU! I would like to know from your experience what’s the best way to buffer RO water’s PH . I’m growing in soil and I was wondering if I just need to add CalMag @ the desired PPM and I’m ready to go ir if I have to add any other buffers. I was looking around and I was reading of people suggesting to PH up the water to 10.0 and then PH down to 6.5 for example. Others suggesting mixing it with 20% tap water,but my water is straight garbage coming out at 370PPMs. So I would be really grateful to have some tips from you guys. Thanks!

I would mix the tap and ro water at 25% tap and should be pretty easy to manage. This is the cheapest and prob best option.

Bigworm4201982 said:

I would mix the tap and ro water at 25% tap and should be pretty easy to manage. This is the cheapest and prob best option.

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I got you,but even if my water is that bad? I find that my plants just can’t stand it. So adding a CalMag supplement won’t do the work?

KasparGrower said:

I got you,but even if my water is that bad? I find that my plants just can’t stand it. So adding a CalMag supplement won’t do the work?

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At 25% tap water the ro mix should be less than 100ppm and thats not bad,, i run straight tap water that is 190ppm no issues.

Bigworm4201982 said:

I would mix the tap and ro water at 25% tap and should be pretty easy to manage. This is the cheapest and prob best option.

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This^^^^ I used to run all ro then 50/50 tap then 75/25. Now I'm at 100% tap<200 ppm. By far the cheapest and best option imo.Water quality dependent.Do you know what constitues that 370 ppm of your water? You are in soil it has it's own built in buffers and organisms that fix it.I'm a soiless guy so I'll stop here. I will say I haven't seen many soil people using R/O water. Again,my soil experience is very limited as is my reading on it here.

CoB_nUt said:

This^^^^ I used to run all ro then 50/50 tap then 75/25. Now I'm at 100% tap<200 ppm. By far the cheapest and best option imo.Water quality dependent.Do you know what constitues that 370 ppm of your water? You are in soil it has it's own built in buffers and organisms that fix it.I'm a soiless guy so I'll stop here. I will say I haven't seen many soil people using R/O water. Again,my soil experience is very limited as is my reading on it here.

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There aren’t any specifict data available on the water supplyer’s website but I live in a industrial town. Right now I’m using orgainc based bottled nutrients and I’m gettin calcium and magnesium deficiencies (both of them) and N toxicity and I assure you I was really really light on feeding N. Im assuming I have a salt buildup on the root zone causing my soil’s PH to drop at around PH5. That’s why I really need a filtration system. Here is known that the water we get from our taps is straight garbage and full of bad stuff so that’s why I would like to avoid even mixing it with RO and if a CalMag solution designed for horticulture would buffer the PH I would be happier since I will have those micros chelates and best absorbed by the roots. I was looking foreward this: http://flairform.com/products/additives/cmx/
It says that it has other micro nutrients adedd besides Calcium,Magnesium and Iron.

They have a new r/o filter out that adds cal-mag back to the filtered water.

Is that different than the 're-mineralization' inline cartridge they do for drinking water RO systems? Since RO doesn't "taste right" to someone who expects it to have a taste. Was wondering about that myself. If it's the same exact thing you know the hydro market will just relabel and jack up the prices.

Here's the issue...the purpose of using an R.O. device is to not use your tap water while watering......and then you want to add it back in?????

Just plan on using Cal/Mag (5ml-10ml) on everything and you'll be good to go. That way you are starting from scratch and know your water is relatively clean of heavy metals, bacteria, etc., etc.

Don't add your tap water back to the mix- stupid idea.

When I use RO I add CM to around 150-200ppm, then adjust PH.

I'd try and get a more comprehensive water report. Usually you can find it on the town /city website. I'm pretty sure it's federal law they make it available. If half your ppms are calmag, and the other half is a blend of other micros like iron, sulfer, copper, zinc, even the chlorine, plus others, it could be beneficial. If it's all chloramine, lead and PCBs keep using RO.

KasparGrower said:

I was looking around and I was reading of people suggesting to PH up the water to 10.0 and then PH down to 6.5 for example.

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Hmmm, never heard that one before! I don't get why you need to do anything about ph with RO and soil?

Bigworm4201982 said:

I would mix the tap and ro water at 25% tap and should be pretty easy to manage. This is the cheapest and prob best option.

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This is the best answer to your question. If your tap water even up to a 50% mix with RO, causes harm, it is not fit to be drinking IMHO
Molasses and crushed oyster shells also seem to do the trick for RO for me.

Cheers

Why bother adjusting ph on ro water in a soil grow? Seems like a waste of time to me. It will buffer to your soil ph in seconds.

RO water has very little in the way of dissolved solids in it, which is the whole point.

From a chemistry point of view, that means RO water has no pH, because there isn't anything there to give it one.

Test your pH and adjust if you must AFTER adding all your nutes. Don't mix with tap water, it defeats the purpose of your RO filter.

Soil does most of the work of buffering so it really isn't all that necessary to balance pH if you're using soil.

Lots of soilless mixes have buffering materials in them. My favorite is biochar, aka charcoal.

I think I’m going to add #PPMs to my RO water regarding the stage of the plant. So a rule of thumb would be : 100-150 PPMs of CalMag for seedlings, 200-250 for established plants in veg and 300 or more for plants in flowering?

ttystikk said:

RO water has very little in the way of dissolved solids in it, which is the whole point.

From a chemistry point of view, that means RO water has no pH, because there isn't anything there to give it one.

Test your pH and adjust if you must AFTER adding all your nutes. Don't mix with tap water, it defeats the purpose of your RO filter.

Soil does most of the work of buffering so it really isn't all that necessary to balance pH if you're using soil.

Lots of soilless mixes have buffering materials in them. My favorite is biochar, aka charcoal.

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When I use CM, I only run it at 150-200ppm up until the last 2-3 weeks of flower. I never saw a need to go over that. I also don't give seedlings anything but root simulators and benes, seedlings don't need nutrients.

I use RO water in soil and what I do is add 2 ml per gallon of fullon to add back some bennies...