DWC bubble bucket ph trouble

Checked ph at 7.4. Used ph down, then is 6.2. Next morning, ph 8.4 and plant dead. 3 week old, healthy, foot long roots on a 8 inch plant. What did I do? Could I have too much O2? I am New to this, any input is welcome.

It’s understandable that pH can be a little confusing. A couple of things to check…

1st, is your pH pen in good working order? When’s the last time you replaced the batteries? Pens do die if your dry out. It changes the chemistry within, and they’ll read wrong.

2nd, Did you use you your device properly? I’m not sure of your experience level, but using pH testing equipment will get easier with more experience.

3rd, Is your pH solution in good standing? Where most Acids won’t go bad, per se, they do get contaminated.

4th, and last, the Yoyo effect. As Acid disolves carbonates within a solution, the results of the process will raise pH again (i.e. Add acid = lower pH + disolved salts = pH back up). This yoyo effect will continue until all the carbonates are disolved.
Once all the carbonates are completely disolved, pH will drop sharply, so be careful not to overdose with pH down.

Here’s a video that might help.

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We’d need to know more about your situation to be able to better help you.

Are you using a 5 gallon bucket, and if so, how many actual gallons of nutrient solution?

Also, as Dumme mentions about carbonates, what is the EC or PPM of your water before adding nutrients? And what is it after you add nutrients?

Do you mean the aeration of your DWC hydroponic nutrient solution? If this is what you are meaning, then no, almost the more air the better, it just becomes almost like an aeroponics system.


The video was informative and easy to understand. yoyo effect probably it. Meter is fine, but my tap water has ppm at 330 and all limestone ground here. I bought new Hi-Flo air pump and am concerned about too much O2 also. I have been trying to learn the needed info to be successful online, but I am extremely grateful to find this forum, as all others were not current. Is there an RO filter I can place over outside faucet to fill my water jugs? It sounds like this will help. Thanks to all…

Too much O2 via air pump, is definitely not your problem. It’s a good thing. 330ppm is fairly high, and will add a lot of Calcium to the mix, that you might not want.

I do recommend an RO filter. Amazon has a ton of choices you might want to check out.


Does the hi-flo actually add or concentrate O2? If it is just pumping in air, there shouldn’t be a problem.

If you are supplementing the air around the plant with CO2, then you want your air pump to be somewhere away from the CO2 so it it will be able to pump fresh air into the water.

But actual air/aeration, no you can’t really have too much. You can have too little.



Now ya have me laughing… new air pump is on top of my co2 generator.

Yeah, I’m almost psychic like that sometimes, lol. :grin:

Lots of CO2 in your reservoir is never good. Place the air pump somewhere where it can pump highly oxygenated air into the reservoir.

Happy growing,



We have a link to an RO unit that would do you good service. It is located in the Buyer’s Guide.

With 330 ppm tap water you are going to have metals that cause your PH to fluctuate. With this said; You need an RO unit immediately. Some users of tap water have no issue but, evidently you have something in the water that needs to be removed.

The only other thing that may cause erratic PH shift is the vessel you are growing in? What are you using to grow in? Did you buy buckets new, or salvage them? What was contained in the buckets originally?

Sometimes it is something we do not think about that causes issues. :slight_smile:


I am using new 5 gallon plastic containers with 4 gallon nutrient. 2 were identical except for the strain in them. Both were treated identically to adjust ph. I did treat prior to ph adjustment for mild root rot with sm90 in one of the plants. BUT, the dead one was the one w/o rot. Survivor doing well was the one with root problem. So my clean container died, and the not so clean one is fine. Did root residue mess affect ph? ppm of nutrients is 300. I switched survivor to new container and nutrient solution. still a bit of brown on roots…sm90 in nutrient solution.

@bryan , one thing you didn’t mention about you ph pen , did you check it with a calibration fluid ?
Hammer .


tes, it calibrated perfectly to solution and to ph test strip. this morning root rot has taken over. is it possible to keep it away, my grow room stays around 82 degrees. Plant appears fine and continues to grow like crazy…

I know people will say your room temps are to high but a friend of mine stays between 78 & 85 deg and never has root issues and he’s using 5 gallon dwc… Check for light leaks in your system… Just my 2 cents… good luck…



I have 3 3/4 inch net pots with 1 1/2 inch rockwool plug inside. When clay went in, it did not cover the sides of net pot; as plant was too tiny then. Now that you have me wondering, I know light went to solution thru the net pot sides above the level of clay pebbles. (as common sense sinks slowly into my brain) lol

That could be it. I started getting a problem. It was that. Not enough rocks to fill side holes in pot. So light leaks between bucket top and rock level. Fix that asap. Try not to let any light in mate.

Yes most definitely no light is the trick plus checking pH and temp of nutes also important

I’ve been having this issue with dwc buckets and that’s why I’m inventing a better way. The problem with dwc buckets is you cannot clean the excess nutes out. It gets stuck in grow media and it settles on the bottom of the bucket changing the ph. Way to cure this is to completely flush media and roots also clean bottom of bucket and sides to remove old nutes. Dwc buckets cannot stir up the bottom, air stones don’t do, just add another circulating pump, yes another plug for dwc. Man someone needs to come up with a better dwc system…Oh yeah I am.

My dwc buckets I had to flush and clean weekly cause it’s a bad design

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Yeah, does seem to need a lot. Of electrical outlets. My room looks like an octopus meeting.


don’t seem to have that problem . are you using nutes specifically designed for hydroponics . i get no sentiments ,build up and i don’t flush when iam ready to harvest i add plain RO to them about 1 week before cutting down . but i do use a lot of air pumps so i get a good amount of circulation in the buckets .unless i let them overroot .



Now that is a root system… Impressive!