The mysterious PH fluctuation

Holy crap! I’ve been dealing with the same issue, and have also been using cheap blue aquarium airstones. I just filled a small bucket with fresh nutrient solution and stuck an open-ended airhose in it to let it bubble overnight, and plan on checking the pH tomorrow. I also put four of the aforementioned airstones (just by themselves, no air) in a bucket of pH 7.0 water that reads 25ppm, and will test that tommorrow as well to see if pH or ppm have changed.

I am very much looking forward to seeing if there’s any useful information to come out of this.

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Not quite. Look at my experiment above with the tap water that had been PH’ed down to 5.11. After adding the PH Down, the PH of the water immediately started to rise back up, and it continued to increase for 20 some hours - until it reached the buffer level of what ever agent(s) was in the water. It started rising slowly until the acid was almost all neutralized, then went up fairly fast until the buffer level had been reached.

In my case, I suspect there are microscopic calcium carbonate particles suspended in the water in addition to how ever much is dissolved in solution. The acid will neutralize the dissolved stuff fairly quickly and lower the PH right away, but it can take time to dissolve the solid particles. So its very possible for the PH Down to drop the PH but then get used up and the dissolved minerals that are still there start raising the PH again.

Also, with that type of stone - made from calcium based rock - the PH would have risen even with no air flowing. All it needed was contact with the water. The flowing air would have speeded up the process though, by constantly refreshing the water in direct contact with the stone.

I suspect something similar is/was going on with my lava rock and perlite. Perhaps they were packaged at some place that also works with calcium based minerals and there was cross contamination on the assembly line somewhere. My water is well water so you would expect dissolved and suspended minerals.

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By the way, here is the definition of “buffer” in chemistry. This is what Im talking about.

A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable.

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@anon32470837, my answers were given by what seemed logical. And you are right about the stone. Yes it would be adjusting the pH even without the air pump, but would probably taken longer to do it. Clearly, since I have never grown in anything other than R.O. water, my experiences are not valid in this context. !!!:confounded:!!!
It just seemed logical that for pH to change in a captured water system, something needs to be added or subtracted from the water. The fact that your experiment works out that way is, to my way of thinking, impossible. It just goes to illustrate that things often defy logic, like a bumble bee flying. According to science. a bumble bee can’t possibly fly due to its weight to wing ratio and the total lack of aerodynamics in its shape.

My water is so bad, I have never even consider drinking it, let alone feed it to my plants. I’d never put a bunch of unknown minerals/chemicals at unknown quantities into my plant nutes.

BTW, I hope you and @legalcanada realize that after your explanations, I agreed that they were possible solutions. I just thought my answer was the correct one.

Thanks for the definition, but it was unnecessary. I’ve been using a pH meter since 2002 when I started growing. :thumbsup:

Edit; made additional comment

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I understand and I was surprised as well. The only thing that makes sense to me is that Im on a well. My water must be over saturated with what ever is buffering the PH up - calcium carbonate or what ever. Adding some PH down, will fairly quickly use up what ever is fully dissolved and chemically available ‘in solution’, but there is still more that is not fully dissolved and ‘available’. Whats left is suspended in the solution as very small, undissolved particles. Its those undissolved bits that will continue to dissolve when the saturation level drops after adding the acid. These are the kinds of things that get filtered out by an RO system.

From what I have recently learned, using RO water can cause other PH swing issues precisely because there are no buffering agents in the water - making it much easier to swing the PH either way with just small additions of acid or base materials…

Me too. Wells tend to fluctuate more than city water due to city water treatment facilities. The minerals in it can and do change concentrations. Sometimes whole filters last for months, others I change the stage 1 (sediment) filter every weekend.

You bet your bippy it can. The R.O. system I use is made for gardeners, its last stage adds calcium and magnesium to about, 30 PPM when new and settling done to about 15 PPM after some use. This is it if you are interested. I bought it at Home Depot.

https://www.theperfectwater.com/Tap-Master-Artesian-HydroGardener-Remineralizing-Reverse-Osmosis-Water-Filtration-System.html

Before September '17 I hauled three 5 gal bottles per week from several different stores. That water was totally empty water. It wasn’t hard to adjust the pH as long as it had nutes mixed it. Before mixing, it was difficult to get a stable pH measurement. It usually ended up to read close to 7.0. I could put just a drop of PH Down and the pH would drop to under 4.0. The first time I made pH water, I dumped out all three bottles of water and went to a different store to refill. When it happened with the replacement, I figured out what was happening, but I still chased the reading up and down until there was enough in the water to allow a stable reading. This is the reason I bought the one that added cal/mag. The pH water measures just fine now.

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Ha! I obviously have no business lecturing to you :slight_smile:
Thanks for the link. I hadnt seen any that add in cal mag before. Interesting idea.

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You are welcome. After I decided just how much R.O. stuff I really needed, I started looking at all the home improvement and hardware websites To see if I could to a cash transaction in person to eliminate a paper trail. I hate that the gov’t can find out everything you do with your credit or debit card without even a warrant. I saw the Home Depot had the biggest selection of R.O. systems available through the website. My mouth dropped when I saw they had 2 systems that will add cal/mag. I bought the Gardener version. The kitchen version included a faucet, pressure tank and float controlled pump. It was more expensive by the cost of the included hardware.

I was buying for my grow water so I didn’t need the extra hardware. It was very easy to setup. It comes with an female hose end attachment so I screwed it on to my basement sink faucet and used it that way until I decided where and how I wanted to permanently mount it.

Making pH water shouldn’t be as hard as it is with r.o. and this system solves that problem. :slight_smile:

Edit: Distilled water acts the same as empty r.o.water, in case you ever have need to know that. :slight_smile:

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I seem to remember this issue coming up years ago after Highgrade popularized DWC in the forums.

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Folk used to think RO water was healthy to drink but now they advise a remin cartridge at the last stage to replace the missing calcium and magnesium. Good news for us growers cos it means the kit and replacement filters are available very cheaply now from the likes of ebay.

So, plants don’t need calcium and magnesium?

I drink my R.O water almost daily when I am working. I probably wouldn’t drink it constantly, but I don’t think a glass or two a day would hurt.

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A small amount wont do any harm but they now say it aint good to drink a lot. They think it helps strip you of minerals same as it does your plants. If you get a remin cartridge fitted to the output of your RO filtration unit then it’s good for you and your plants (we should all be drinking water with some mineral content) That is the advice i got from a few sources when i looked into this last year.

It’ll all change again soon no doubt so do what works for you :grin:

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this is going to be politic @LemonadeJoe, this was the Breakingpoint. I just ask for discrete observation before things get messy in abusive language, @Scissor-Hanz.

I think it depends more on naturally waterform (pref.energized) Schauberger principles, and… now it comes, any negative substances of harm for human and nature. This excludes also Hormones of any kind, It has been proven, that reenergized Water made of destillated Water is a good drinkable Source in any Situation, it does not harm you in any way and is good for you. You can uptake Minerals via Food in much higher amounts, it mostly depends on frequency of the water.

Throwing out the stone I just bought. CHEAP blue stone.

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That sound like a good idea, @G-paS. You can get air tubes like some aquariums use. It is a plastic foam of some sort and won’t put any thing into your water. I learned that here 15-16 years ago. :wink:

I was only going to use it for making tea but already have ph issues.

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I only drink RO water. our city water has fluoride in it and i want no part of that. plus i love the taste of cold clean water. one of those office coolers is probably the 2nd best purchase i ever made, after my grow equipment of course :smiley:

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RO water does taste good chilled, but it’s chilly here most days so we drink coffee, tea and alcohol mostly :grin: We do have water issues here, we have so much falling on us almost daily but the stuff coming out of the tap still tastes crap and smells of chlorine.

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Im not using “stones” at all in my hydro system. Stones also tend to plug up over time, and they are a pain to clean, plus they are $.

Most importantly, you really dont need those tiny little bubbles. They dont add any more O2 to the water than a simple fluming setup. Just having a stream of bubbles lifting water from the bottom of the rez and “fluming” or roiling the surface works just as well or maybe even better as far as adding O2 to the water. Water falls also work well.

I made some “air non-stones” for my rez by just taking some small plastic tubing that fit my air lines, and crimping the end down until there was just a very small hole. Like the size of a large sewing needle hole. Maybe 1/2mm or so. You could also just fold over the end of the airline and then punch a small hole in the tubing.

I zip tied a piece of lava rock to the end of the airline to keep it on the bottom and thats it. I have 4 of them running in my rez.

Actually, since I have a piece of lava rock on the end I guess it is an air stone after all :slight_smile:

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