RO drops water pH to 4.9, does it matter? Alternative to pH up?

I grow in 5 gal buckets of organic soil, mix it myself, follow subcools recipe pretty close.
My tap water = 6.5pH 250ppm ... After RO = 4.9pH 25ppm

250ppm burns my girls, 25ppm is too pure, I find they like 100ppm best.
So, I have my res set to fill with a mix of both RO and Tap, I use a pressure regulator and adjust it so I hit 100ppm, but pH is still low @ 5.1 after the mix.

Now I've read organic soil with dolomite lime is suppose to 'maintain" a pH of around 6.5,.... but that's just really hard for me to wrap my head around. Why? I put a handful of dolomite lime in the bottom of my watering jug a few weeks ago, and its still there. I tested and it didn't effect pH in the jug one bit no matter how long it stayed in there. I find it hard to believe just because its in my soil, it, or anything in my dirt, will make water with a pH of 5.1 instantly adjust to 6.5 when it rushes over it. I've read folks say your waters ph doesn't matter in organic soil, but I ponder if those folks have ever poured 5.1 pH water into 5 gal of soil from seed to harvest. It's never worked well for me.

Right now I adjust my RO water to 6.5 with pH up,. but I hate the shit. It doesn't dissolve fully in water and clogs up Blumat drippers. I'd prefer something that ADDS to the taste of the plant too,.. but I fear anything natural would be too weak to move pH enough and or keep it where I want it long enough.

As is, I add about 1ml of pH up per gallon to my res. I tried lemon drops once when I had to adjust pH the other way, but it took way too much. I would have had to plant a lemon tree orchard to keep up, lol.. Or can someone really convince me why it doesn't matter. If it doesn't matter I should be able to lower the pH even more before pouring it onto my soil, haha. this would not go well. What the hell can I use to naturally move my pH up? Anything natural and relatively concentrated?

Have you tried using just tap that you set an air stone in for 24 hours or so prior to using? That would take care of most of the chlorine and youd have some of the calcium they add to the water. Or is your tap a high ppm?

Also is your r/o new?

I noticed that the first month or so of running it my water would come out similar to yours. 4.5-5.5. But after that it came out pretty constantly at 6.5-7.2 (our tap starts around 8.5) And now i can tell its loosin its spunk cause the ph is drifting up every month. Ive had it for about a year and its rated for 100 gpd and i run it about 10 gallons/week.

budbro18 said:

Have you tried using just tap that you set an air stone in for 24 hours or so prior to using? That would take care of most of the chlorine and youd have some of the calcium they add to the water. Or is your tap a high ppm?

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DIYer said:

My tap water = 6.5pH 250ppm ... After RO = 4.9pH 25ppm

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I can't use the tap straight, RO isn't new, and the system doesn't stop dropping pH to 4.9 unless the filters are a year old and in need of changing.

I think I need alternatives to pH up.
Something organic, something natural, something that adds to the flavor,.. and in a perfect world concentrated too, ha

I have the exact same problem. I use Earth Juice Natural Up and Down crystals. A little bit goes a long way. My RO ph is 5.6ish and a small 1/8 tsp of the Up brings it to 6.6. I grow in TLO style and if I didn't adjust my ph things would be bad. I had some lockout issues before I decided to adjust my ph. I decided to adjust my ph from that point on.

I just finished an organic soil grow and went though the exact same concerns. DON"T use ph up/down with supersoil or any organic soil. It fuks up the the microorganisms that are suppose to be helping with the buffering in your organic grow. It took a lot of convincing myself and I watered with a PH between 4.7 and 5.2 in 7 gallon pots. Check out the runoff PH with the first water that comes out through the bottom of your pots and you will see the amazing buffering capabilities of organic soil for yourself. But don't get too hung up on your runoff PH either because the lime and microorganisms adjust acid/base to what the plant requires at the time. Do you PH your water for tomato plants? I seriously doubt it. Many organic growers don't even own PH or ppm meters...

Okay, with all of that said, I had better check with you to make sure you've added the appropriate amount and type of lime and epstom salt to your supersoil. Epstom salt is in the mix to help with the magnesium. How much and what type of lime (dolomite?) did you add? How much Epstom salt?

^I agree with you about the PH adjusters killing bennies, but not about having a 't' in "Epsom".

LOL... it's a bit early for me and yes... I can't spell worth a damn but I think Cannada is spelled Canada...

DIYer, I highly recommend that you read "Teaming with the Microbes". It will help you understand that there is much more than just the lime involved in buffering acid/bases and the symbiotic relationship that bacteria/fungi/mycorrhizae have with the plant. It opened my eyes more than any book that I can think of at the moment...

Boy do i have a hard time doing what you're saying Crab Pot, not the reading about good microbes in the soil part, I've done that, I didn't know ph up was bad for them though. Cant be too bad as I think my ladies are looking lush well i know they're looking lusher than ever anyway.
Thank you organic soil.




I did hydro for 6 years, this is my first soil grow so what do I know, but soil seems like a sponge to me, I'd assume strongly its only going to be the pH of the moisture we put in it. I mean no one here would tell me its wise to drop the pH of my water even lower than 4.9 right? The soil can't do it all, even if I am adding Epson salt and dolomite lime to my soil mix, which I am, how much?..i forget exactly, but i follow subcools recipe. I'm about to mix up a new batch so I can do whatever,.. but still hows the soil do it all? It just seems like 6.0-6.5 going in would be better. That's what I've been moving it to,.. friggen hate ph up though!

I'd like to just use the tap water, but who knows what I'd have to cut out of my soil mix, its just too rich coming out the tap, i got a lil tip burn as it is I don't want more... don't wanna start putting 250ppm on those flowering ladies with a month to go, even if my tap water pH is nuts on.

I've also got a veg room (not pictured) and they get water from the same res. Don't think I want 250ppm water on my lil ladies either. I feel like I gotta filter it a bit, but then pH is way whack. Hate buying from the hydro store too, they get enough of my for bags of Roots, but i might have to try this earth juice, i hear a lot use it.

Yep... seems like it to me too but your stressing the microbes at the least...

What about your other plants? are you PH-ing their water too? Hell, watch out!... they might have nute lockout soon too... I'm just kidding but hopefully you see my point...

PH with synthetics because synthetic fertilizers kills the soil microbiology. Keep adding that PH up and you will need to PH your water for your "organic" soil...

DIYer- Honestly, I only mean to help you. Like I mentioned earlier I just went through this myself using a modified supersoil. I was afraid that as soon as that 4.9 PH water hit those roots those plants were going to go into immediate lockout. But, no that doesn't happen. Your plants look okay but they're still dealing with that crap your giving them. What brand of PH up are you giving them? Actually, it doesn't even matter... stop it... if you don't believe me... try it with one plant...

"stressing the microbes at the least" is what I thought too. I would like to try it with one plant, but I love taking as much work out of two grow rooms as possible so i automate the watering, they all get watered from the same 100 ppm 6.0-6.5 pH 5 gallon bucket, and it gets auto refilled half tap, half RO. With the right soil I just clone, train, trim, and harvest. I did brew teas twice this grow.

How much Epson salt and dolomite lime per 10 gal Roots bag would you add knowing 4.9 pH is on the way? I just bought more ingredients to mix soil, I'd like to know what someone who does it with low pH RO water would add. I mix in my apartment so i only use 20 gal cans, 1 bag of Roots fits in there nice, then i add the ingredients, cap lid, and roll it around to mix. Below is my recipe (in these is what I really add) I cut everything down by 8.


8 large bags of Roots (1 bag)
25-50 lbs. of organic worm castings (5 lbs)
5 lbs of steamed fish bone meal (.6 lbs)
5 lbs Bat guano (Bloom formula) (.6 lbs)
5 lbs Blood meal (.6 lbs)
¾ cup Epsom salt (divided by eight)
1 cup Dolomite lime (divided by eight)
½ cup Azomite (divided by eight)
2 Tbs. powdered Humic acid (a pinch)

Oh and since i use RO i add oyster shell powder for calcium. forget how much,..prob 1/8th cup

You have the proper amount of epsom salt and dolomite lime in your mix. Tap water contains magnesium and calcium which plants require and RO water doesn't. Typically calcium and magnesium are added back to RO water at approximately 100ppm and more for heavy feeders. General Organics Cal-Mag+ is the only calcium/magnesium supplement that I am aware of that is organic. You may be okay with your water mixture at 100ppm but keep an eye out for a magnesium deficiency. I believe Sub recommends molasses at days 30 and 45 and molasses is packed with magnesium.

I understand that 4.9 PH sounds off the charts but it's right in the range that most organic farmers water at. Most things we add to the water are acidic. RO water is buffer-less and your going to have huge PH swings compared to a buffered water, such as tap water.

I did an experiment when I was having a difficult time understanding about PH-ing organics myself. I watered at 6.5 PH and the runoff was at 5.8. Okay, then I watered at 4.9ish PH and my runoff came out at 6.6. Try it for yourself. The mix (including the microbes) does buffer 4.9 PH water with ease.

I don't mean any disrespect and I hope you understand that I'm just trying to help you. But, if you want to grow organically... then get rid of that PH up crap...

Great post Crab Pot. Thanks for sharing that. I have watered with hard well water, and straight RO water. As Crab said, the microbes control the soil. My next grow will be RO water with a pressure pump to run through a Blumat drip system. I'm anticipating RO water and building the soil accordingly. I have looked and looked at any available data I could find, and aside from pollution, rain and RO are about the same. Pretty much pure water with dissolved ions.

No I hear you man, its all good, and I appreciate the knowledge drop. Just to be sure,.. you didn't do that watering test before and after light flip did you? I forget which way it goes, but remember from my first ever grow, which was soil, that runoff changes from veg to flower. I'm sure what you do works for you, just want to make sure before i turn off the pH up faucet.
Fuck it I'll try 100 ppm @ 4.9 pH for a few days. I'm going on business to CO for a week in 10 days, if nothing goes south in 10 days it should be good, and I'd feel a lot better leaving without having to worry about my pH doser dosing right.

Oh FYI,.. I don't water enough to get runoff. I've got how much I water set pretty just right (I thought),.. am I suppose to have some runoff? Or just make some for a pH runopff test to sooth my worried mind?

Rrog said:

Great post Crab Pot. Thanks for sharing that. I have watered with hard well water, and straight RO water. As Crab said, the microbes control the soil. My next grow will be RO water with a pressure pump to run through a Blumat drip system. I'm anticipating RO water and building the soil accordingly. I have looked and looked at any available data I could find, and aside from pollution, rain and RO are about the same. Pretty much pure water with dissolved ions.

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I was so high on the Blumat drip system man, and my pH up clogging the Blumats aside, the problem I have most with them is they only water at one spot. They're expensive as it is and you might end up needing 2X more than you think. I bought the long Blumat's too, still I find in 5 gal buckets you need two, one on each side of the stalk. I got this one girl who's a drinker, forget about it, I gotta have two or one side of her is limp all the time, and the other drips slow 24/7 with no runoff. That can't make for the best bud. I really started to think they needed water all over. I used Blumat's in my flower room for a few months, but found they really need pure water or overtime they'll clog and you'll dry up a lady if you go on vaca. They're touchy,.. water too much or too little IMO,.. and like I said all in one spot. Sometimes water just finds the path of least resistance through your pot and a good chunk will remain dry. You might not see a problem with the plant, but you also for sure wont see as big a nugs.

I came up with a much cheaper and I believe better drip system. I used 1/4" soaker hose, made rings around the stalks. I wired a cheap $15 12V solenoid to a $5 12V wall wart, and plugged it into a $5 timer from home de pot. The soaker line was cheap too. Two Tee's per pot and bam, I got water happening for 1.5 hours everyday when i want and expect it to, cant have that with Blumat's. They over water when you're not home sometimes, and they do if you have them inserted wrong, you've got a lil mess to clean up later perhaps. I know I did.

My res is elevated so watering is all gravity's job (K.I.S.S.)
When the timer kicks the power plug on it opens the solenoid and gravity waters my ladies, all over. This has to help them grow roots all over, and use all the soil i paid for not just some on one side the pot. can add or take away watering in 30 min chunks, with a $10 weekly timer could do it the days i want,.. but i water everyday for 1.5 hours and they seem to like it.



PS: Even this soaker line will drip less and less the more pH up i run through it. I found a trick though,.. if you bend/kink the soaker line for a sec it drips at that spot again

It's important to water your medium evenly as you now know and that includes the bottom of your pots. So, yes you should have a small amount of runoff and the plants will suck up the extra runoff water in a few minutes anyway. You don't want any dry spots in your medium after watering. It's real difficult for the microbes to live in dry zones...

I like that you are going with the KISS approach and all of your automation. Let us know how it works out for you.

A few quick things.

Dolomite lime: 1cup/cf of mix or 2tbl/gallon of mix. That would be ~20tbl for your 10gal bags. It's just finely ground rock, so big surprise it didn't dissolve in the bucket of water. Use the right amount and it will take care of whatever pH dumped on it.

It also provides Ca and Mg. The Mg is a bit slower than the Ca breaking down, so I add a bit of Epsom Salts to the initial mix. A good handful to 2cf (15 gallons), which is the amount I mix up at a pop. It's a good wheelbarrow full.

PRO-TEKT from Dyna Gro is a silicon supplement ok for organics and is also a handy dandy pH up. I use 1/4tsp/gallon of water once/week. Do some searching here and in the nutrients section for plenty of info. I don't use it as a pH up, but for the silicon and the K. It's 0-0-3. Good stuff.

You sound on the verge of over thinking this organics thing. Don't! It's not all that complicated. I haven't used my meter in over 2 years and never noticed the difference.

Wet

That's the 1 big draw back to using RO'd water. It completely strips the water down, even the good things you need that's in the water.
Imo if you don't have your nutrients dialed in, then it's best to stay away from the RO'd water until you do. jmo

RO = rain, so when we talk about stripping the water, we'd have to be talking about stripping minerals from hard well water of municipal water. If there's proper initial mineralization of the soil weeks before planting, no worries.

No worries = No CalMag+?

RO = rain? I thought it meant reverse osmosis

I hear ya hydrogreen65, that's why I run two water lines into my res, Tap and RO. The tap water has endless pressure, the RO system does not, so I let the RO flow full, and with a pressure regulator I choke the tap water down to just enough to make a refill hit 100 ppm. Best of both tap and RO worlds IMO.

I used a silicon supplement once when doing hydro and saw zero effect. I read what its suppose to do for our ladies, and I'm sure its good for mj,.. maybe I bought a shit kind or something. Does anyone ever SEE the results of Silica Blast? Hey now that I think of it, 'Silica Blast' was the kind I used, haha