# Why does the ph drop from 6.2 to 4.9 with in a day !?!?



## JackRush (Jan 31, 2011)

My friend has just finished his second week of flowering in a vertical system that looks like this one -> ( http://www.hydroshop.ca/english/ecosystem-vertical-growing-system.html ) . He is using grodan v-slabs made of rockwool. He seems to have a major ph problem now ! Even if he changes his reservoir with fresh new solution, his PH drops by 1.2 points within the first 24 hours !!!!!!!!! He starts if off at 6.2 and everytime the water goes through his slabs it comes back .2- .3 points less ! 

Here are some notes that might help u understand his system better

- He doesn't have a drip system but rather a strong spray at the top of the slabs
- He sprays 6-8 minutes on and 45 mins off
- his solution consists of 800 - 900 ppm of A + B from Nutriplus ( http://www.nutri-plus.ca/ ) some PowerPack and some B1 ( he will stop using the last 2 this week )
- He sets his solution at 6.2 and after just one feed of 8 mins it drops down to 5.9 !! and it keeps doing so until it hits 4.9 within a day or less !

What should be done ?? I don't think adding ph+ a couple times a day is very good to the plants

Thanks


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## stumps (Jan 31, 2011)

did he set up the the new water and let it sit for a day before going in the rez? could be something in the water going up and down. I hope someone pop's in and explains what I'm trying to say.


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## JackRush (Jan 31, 2011)

No he didn't , would that change anything ? I know letting it sit will only get rid of the clorine


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## lowerarchy (Jan 31, 2011)

Sounds like pathogens in the rez, possibly growing in the pump/fittings/tubing or something in the reservoir. If he lets it sit in the rez for a day and the pH still starts to go down, that's the issue.

Otherwise, I'm stumped. No real reason for pH to go down if everything is otherwise healthy and green. I would clean everything thoroughly and blast a new rez with 30%h2o2 at 3ml/l for a while.


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## stumps (Jan 31, 2011)

Ph is a strange creature. Have you checked the tds in the water? How do you adjust your Ph? I know if the tds is high it can do strange things when you add utes and such. could even be the nutes doing it. But I'm no expert.


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## JackRush (Jan 31, 2011)

Yeah I checked the ppm which is around 800 . I don't know how much that is in TDS. He ajusts his ph with PH + -> http://www.nutri-plus.ca/hydroxyde_en.html


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## stumps (Jan 31, 2011)

I wouldn't drink it. Good is under 200. I can't find my chart but I think 800 is way frigging high. My well runs 195-230. Is that drinking water?


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## JackRush (Feb 1, 2011)

My apologies ! The final solution in the reservoir after nutrients have been introduce is 800 ppm. The water itself is around 200 ppm


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## supersillybilly (Feb 1, 2011)

If you adjust your ph before adding nutes then thats your problem.


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## unity (Feb 1, 2011)

They are taking up more water then nutes, which in turn causes your remaining solution to go 'hot'. It is very normal to get a ph drop the first view days, especially in a new res. if it is a bit 'hot'. What is happening to the ec in that same 24 hour period, that ought to tell you something. If the ec is going up (like I suspect) then just add water back in until you are back at your starting point ec. That should also get your ph back up a bit, the rest you have to adjust with a little bit of ph up, or silica. Next res should be a bit weaker, until you find equilibrium. 
If your ec does not shoot up during the same 24 hours disregard what I told you


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## stumps (Feb 1, 2011)

that sounds like a good idea.


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## JackRush (Feb 1, 2011)

Ok, the representative from Grodan ( the one who make v-slabs which are especially for vertical growing ) mentioned that since my friend only waters 6 minutes on/ 45 mins off, some roots must be dying since they are not watered enough. He suggested to water 10 on/10 off. He also said that he suspects that the dying roots is the reason why the ph is going down ! !

What do u guys think ?

p.s. Unity mention that if the plants are taking up mostly water and leaving the reservoir more concentrated with nutrients that the PH would automatically lowwer. But In that case I guess that the PPM would increase....but that is not the case here. Level of concentration of nutrients remains the same.

Also keep in mind :
-this crop is only 3 weeks old 
-the best quality products are use ( a complete nutrient product, Power pack and some B1 ). 
-Reservoir temp is 20-22 celsius ( 68-72 ). 
-Room temp 25 Celsius 
-Co2 is added to the room

This was not happening in the first 2 weeks !

Thanks


The system is not a drip system but rather a " sprinkler " system


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## unity (Feb 2, 2011)

Yep, if the ppm doeas not increase my theory is out the window


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## unity (Feb 2, 2011)

Maybe some rockwool guys can chime in, I have moved on from the stuff years ago due to these kind of problems. Having said that, countless people produce excellent crops with with rockwool. From what I remember rockwool is very finicky with watering intervals, needed runoff etc.


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## rosecitypapa (Feb 2, 2011)

Isolate your problem, take your plants out of the equation. Mix up a reservoir of nutes and leave sit for at least 24hrs, adjust ph and keep it sitting until it's stable for 24hrs. If your tds meter is calibrated to potassium your levels are fine but if it's calibrated to sodium, you are running hot.


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## jarou (Jun 20, 2011)

Had similar issue, added the H2O2 @ 3ml per/gal, then 1.5ml per gallon next day and issue resolved... at least with the PH... nothing else noticable!

Thanks!


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## GoldPT (Feb 3, 2012)

Hi guys,

Im new into the forum! I've started lately into hydroponics with aeroponic system and google directed to this topic since i've exactly the same problem....

JackRush: I've exactly the same problem... Did you found a solution? I adjust the system to 6.1 and 24h/later it drops to 4.3 

Thanks


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## JackRush (Feb 4, 2012)

If I remember correctly, he changed to Canna products which helped a whole lot !!!


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## nitro harley (Feb 4, 2012)

JackRush said:


> Ok, the representative from Grodan ( the one who make v-slabs which are especially for vertical growing ) mentioned that since my friend only waters 6 minutes on/ 45 mins off, some roots must be dying since they are not watered enough. He suggested to water 10 on/10 off. He also said that he suspects that the dying roots is the reason why the ph is going down ! !
> 
> What do u guys think ?
> 
> ...


Hey Jack....

On my last grow I went through this same problem...into my third week of veg my PH started crashing in one day just like you are saying....My plants were green a healthy looking but they weren't growing..the roots were brown and whimpy....They were starting to die....

I was able to save them with a 29% H202 [email protected] 20ml per gallon for three hours then I pumped the buckets out and did it again for another three hours...then I cleaned everything the best I could with fresh water....Then I added some benny's called actinovate....4 teaspoons in a gallon and a half of water and then I split that up between my six buckets....Then I added fresh nutes and in about three days we had new roots growing the PH leveled out and everything was happy again....hope this helps.......nitro....


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## Refusedpanda (Feb 4, 2012)

So the NutriPlus nutes are junk? I have two boxes full of nutes from them I got at a show. I was going to use them next run, but if that shit is causing problems I will just give that stuff away.


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## unity (Feb 5, 2012)

Guys, if the h202 is 'saving' your plants then you have environmental problems, i.e. your nute temps or watering intervals or water quality is off.
There is nothing wrong with h202, just keep in mind it wipes out all the beneficials as well and you will have to do it ever 2-3 days. And it is rather expensive . 
I would use it as an emergency while I figure out my environmental issues.

Kind


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## JackRush (Feb 5, 2012)

Refusedpanda said:


> So the NutriPlus nutes are junk? I have two boxes full of nutes from them I got at a show. I was going to use them next run, but if that shit is causing problems I will just give that stuff away.


I don't think Nutriplus is junk, it's just that Canna is top notch and it made a difference in this case


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## Cabledude4619 (May 11, 2016)

I'm having the same problem with ph going from 6.1 to 4.9 in a day. I'm running a waterfam drip system with a air stone in the res. Ppms are are ok at about 800 or so. Roots are hanging in the res and are super white and nice. Was wondering if the water coming from the drips are leaving nutes behind on the clay balls thus returning straight water back to the res causing the ph drop. Anyone have this problem? The plant looks super healthy and bushy and green. What I did was disconnect the air line to the drip ring and just leaving the air stone on with the roots hanging in the res, gonna let that go like that for a day and see if my theory is right. I'm using GH nutes using the Lucas formula with floralicious Plus as the only additive. Any help would be greatly appreciated.


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## Cabledude4619 (May 11, 2016)




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## Cabledude4619 (May 12, 2016)

OK update, I disconnected the drip ring and just running the air stone and the ph is holding at 5.98 this morning. It was 5.99-6.0 the night before. So I think I have the problem fixed


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## Dreamwalker_j (Feb 21, 2021)

Jey i know this is a late reply but for anyone who still needs help.... 1 word........ algae. If your plant sites are not protected from light they will grow algae and that algae will make its way back to your reservoir. It doesnt take much to make your pH crash from 5.8 to 4.9 in 24 hours. If you have a venturi pump in your res like i do, instead of using air stones, that pump filter will grab all the algae and pump water through it making the pH crash. Clean the pump filter and lower your water level by an inch so that when the system floods it doesnt reach up to the algae, then clean what algae you can off the top of each site, rinse with dilited peroxide (cant remember the strength) and you're good to go. I've dealt with this and was able to fix it WITHOUT dumping the reservoir. If however, the pH changes in your reservoir without cycling then theres a good chance you have a pathogen in the system somewhere and the whole thing (reservoir, hoses, pumps, buckets, everything) needs to be purged and flushed with peroxide water, then rinsed, then you can refill. I hope this helps someone. Happy growing, friends.


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