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pH Changes - Hard to Control

O

OU812

New member
Started germinating seed 7/22. Set up seedling in Hydrofarm DWC Bubbler. Using Viparspectra 450 in a 32"x32" tent with good ventilation/air circulation. My tap water comes out at > 9 pH. Using Fox Farm nutes for hydro, full strength at this point. Replacement water w nutes always adjusted to between 5.5 and 6.2. Within a day, pH goes to > 7. I'm changing the water every other day to bring the pH down but, doesn't stay there. Using Hydroguard, too.

I tried 1/2 strength nutes, RO water w cal mag. Nothing helps to maintain pH within range. I've read and re-read everything I can find on here about hydro and bubblers and can't figure out what I'm doing wrong. Any help anyone can provide will be much appreciated!
 

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Are you using ph down as well? Perhaps have a second pump go until your ph stablises in a bucket, add ph adjustment as needed prior to feeding.
 
Assuming you are using pH down, what happens after few days if you adjust pH instead of change? What is water temp? Does EC go up or down? Are you using silica?

I have to mix my calmag and silica, with a pH adjustment, the day before. It stays more stable that way. I do believe pumping a lot of air through the water raises pH, although I doubt you are.

is that the current plant you are growing? Full strength nutes is a lot for a plant that size. Have you looked at the roots, if it has any to see? Campesino let me know that a bacterial infection can raise the ph but the EC needs to drop I think. He would have a lot more insight to your problem.
 
it sounds rather simple to me, your very alkaline tap water must have high concentrations of something the plant does not use (like sodium) so when it uses the nutrients all thats left in the reservoir is what ever your tap water contains. try using only RO water and nutes,
 
Yes, using pH Down. I'm not sure I understand your recommendation to use a 2nd pump, etc. Would you mind elaborating a bit? How does this work? Thank you for your help!
 
Yes, I am using pH Down to bring the pH down to where I want it (at this point, 5.5). After a day, sitting in the container before adding to the plant setup, the pH creeps up to about 5.8. There are no roots to see yet however, I've been adding Hydroguard with all the water I've used.

Today, temp is 82, rH is 41, pH is 7.4 and, ppm is 634. I added pH Down to reduce pH to 6.5, ppm unchanged. RosettaStoned and Campesino - any thoughts? Thanks for your help!
 
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Sounds reasonable. I did try RO water, nutes, with CalMag and Hydroguard. The pH was just as unstable - shot up > 7 by the next day, as it has with tap water plus Hydroguard.
 
Second air pump to circulate the nutes and balance everything out prior to giving the new mixed nutes to your plants. You can adjust the ph that way.
 
Geez then I got no idea what it could be. Like the others said. Without EC readings it’s very hard to know if it’s a small phenomenon when nutes are used and a very little concentration of something else remains or if it’s a big problem impeding nutrients from being absorbed. The plant is still rather small. You will have to keep an eye out for deficiencies caused by too high ph in order to react. The whole issue could go away as the plant gets bigger and drinks more
 
I am tracking ppm. Today, it measured 634. My (limited) understanding is this represents about 1/2 the full-strength nutes - about what this 2 week old plant needs? It's growing nicely and doesn't appear to be pH stressed so, perhaps I'm over-thinking it. Thank you for your help 9fingerleafs - much appreciated!
 
No worries :) in that case consider your ph pen may need calibration? If the plant is healthy and happy don’t hange a thing. Btw I feed the same dose all cycle around 2 EC or 1000 Ppms.
 
Changed over to RO water last weekend. pH is still hard to control. Measured this morning and pH was 7.1 545ppm. Used GH nutes this time and the water needed no pH down - got to 6.0 on it's own with the GH nutes. Left it sit for a couple of hours and still 6.0 657ppm. And, here's latest pic. Seems the brown spotting isn't as widespread as it was a week ago. Pruning the f'd up leaves (once more than 50% spots). Tent temp is 79 degrees, rH @ 51%. I added an airstone to the reservoir, checked light placement and fans and all is set up well. I wonder if it was the Fox Farm nutes f'ing up my water?!?! The GH nutes feel better (to me and, hopefully this little bitch). I've calibrated both my meters. I want to thank everyone for your wonderful suggestions! Gave me a lot to consider and research. This is only my 3rd recent grow. Hopefully, I can fine-tune my setup and get a decent yield. I tried coco, super soil and, now, DWC. Couldn't get pic to upload. I'll try again later today.
 
My set up for future is gonna be dwc along with top feed rings for drip feed, looking forward to setting up a hydro system, RO water well I also considered this, however, now I use it for drinking, and not feeding my plants, since I use soil right now and don’t want to add too much nutrient. RO for me will be for flushing I guess
 
Top feed rings only benifit the dwc when it is a seedling . Once your roots hit the water they are useless . Just something to think about before to spend money . You can eliminate the top feed all together and just water by hand twice a day from the res with a cup . For the limited time the top feed will be used I don’t think it’s worth the money imho
 
Can I see a photo of the roots please ? And a photo of the water in the res with the pumps on . Even if no roots showing please still give pics of net pot and res water .
 
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Yes I know top fed is only good when they are small, so do continue to use em late into their grows I see, but I would use it just at the beginning before root zone is in the res. Thanks dank, good advice
 
It's almost impossible to know what the ph of RO, water is, it's supposed to be close to 7.0ph, but that ain't always the case.
RO, water is to expensive and a big waste of resources if you ask me.
But lots of people use it ,still.
Good Luck with your plants.
 
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