Non feedings using R/O water?

Hi! I’m adding an R/O system to my sink because my tap water that I have been using starts with over 500ppm. I’m wanting to switch to r/o to have a cleaner starting point.

My question is this, when using r/o water I know that I will need to add calmag, but always in the past when using mainly tap water, I will water the plants with nutrients once or twice then I water once with no nutrients added.

Now that I will be using r/o water for my plants instead of my tap, can I still stick to the water with nutrients once or twice then just pure r/o water schedule… Or what would be the best way to do it?

I don’t like the idea of adding nutrients every single time I water water but if that’s the solution that’s what I will do.

And if I can still stick to my normal schedule of water once or twice with nutes, then once without… Do I need to add anything to the r/o water on the non feeding water?

​​​​​​​Thank you!

1 Like

Your feeding routine will be determined by the previous run off PPMS. Soil likes a feed, water feed with a dry cycle between each. All depends on the PPMs from the run off, you could have back to back watering or nutrients and always to liberal run off of at least 20% coming out the bottom of the pot of what you’re putting in :love_you_gesture:


I do a feed feed feed flush with my RO set up and things seem to stay about where I need them.

1 Like

RO is PH unstable. So is distilled. On water only days you will need to add enough calmag or epsom salt to bring your tds up to 3-350ppm and then ensure ph of 6.8. Water days are ment to adjust the ph of nutes in soil zone so you want that water ph stable otherwise your soil will adjust your water vs water adjusting soil. Ive alwats done feed water feed water but @OGIncognito is right best to feed when tds of runoff is below 1000. It just happens to be in that order more often then not.


What about waterings during the final week or two before harvest, do you still want 300ppm to get the ph correct? I was under the impression that at that point you want as few nutes as possible.


Depends on your methodolgy. I have read that watering with water that is 10ph will give you pretty red colors on the leaves. Ive not tried it. If you did that you would want ph stable water. Outside of something like that your good with just pure water.


I thought you might say something along those lines. In this pursuit, there seems to be many gray areas with probably know real right or wrong answer, just differing experiences and opinions. I’m thinking for my final 2 weeks I’ll use a table spoon or two of my FF Bembe and a tablespoon or two of Cal Mag, to get up to 200-250ppm for the first weeks waterings, and two final good soakings for my final waterings with just my source water which is about 70ppm. Giving it 3 days or so to dry out prior to chopping. I’ll use correct ph the first week and not worry about the final week. My plain water is 7.3 anyways.

1 Like

Thats alot of calmag. I use at the most 5ml (1 tea spoon) per gal water.

1 Like

Ha. I’m putting it in 5 gallon buckets. I actually ended up using the Fox Farm schedule and just cut the amount by 1/4, so didn’t use cal mag at all. I’ll just keep reducing the FF nutrients (bembe, tiger bloom, big bloom and cha Ching) until I end with a couple plain waterings. My ppm was about 250ppm when I fed this morning.

1 Like

Question for you did you get a pump with your ro system or no. Asking cause I just ordered one and it didn’t have a pump so I was wondering if I would or could make it work.

1 Like

This is the one I got. It hasn’t arrived yet! I did a bunch of research first and this was the #1 overall pick from most of the websites I looked at.

APEC Water Systems Essence ROES-100

I did however get a 2nd, 4gal tank for it so I’ll have more water at once and not have to wait for more.

I did not buy a booster pump because I have good water pressure, but we will see what it’s like once I get it later this week and install it. If need be I will get a booster pump. I did also purchase a pressure gauge for it to see how much psi my flow is!

I got a RO system i hooked up from a y junction off the cold water hookup then run the line to a 55 gal plastic drum that has a pump head so i have 55 gal on tap when needed and its super convenient. My 55 gal drum had food safe silica in it and only gets used for my plants but i have tasted the water before and it tastes fine

So I have 65 to 70psi. Let me know how it works for you with no pump. That will determine if I send mine back.

It’s OK. I’m at 45psi. For only 4 plants I probably won’t add a booster pump. If I had more plants I would probably buy one.

But I save my gallon jugs from distilled water I use in my humidifiers and fill those immediately after watering… So I never need more than a few gallons at a time since I’ll have a handful of gallons at any given time ready.

1 Like

I have the same model and it works with my 65 psi…it is a little slow…I go right into 5 gal pails

1 Like