PH starts to rise....help wanted

[rajen]

Hi folks,
after scrolling the forum for answers I try to ask my specific questions here.
I hope someone can help.

I´m running a rdwb in 8 28 l buckets.
My res. takes about 70 l, from where I pump the solution to the buckets. (to recirculate the whole solution it takes about 45 min.)
The bubblers and the waterpump run 24/7).
When I started the ph and ec was rising.
Now 5 weeks before harvest (slh) the ph is falling from 6.2 to 5.3 in one day.
I keep the water at 18-20 °C.
I use GHE bloom and micr, some min. magic, supervit, and hesi enzymes.

when I keep the water for a a day the ph falls too.
The roots look good, the bubblers are working fine, and there is no polution.
I also changed the solution but couldn´t eliminate the effect of falling ph.
My meters are new and calibrated perfectly.

what could be the reason and how to fix it.
i don´t like putting too much ph+ because the ec rises and I need that for fertilizers.
the plants look quite good for resin production, but the buds could be bigger, that´s not really my concern, as I expect the buds to grow bigger at the end, but I´m afraid of a lock out.
I also know that the rise and fall of ph is good within a certain range, so the plant can take what´s available in the solution at different ph.
Maybe someone has experienced the same and give me a hint in which directin to look. Thanx in advanced and keep it growing.

 

[hempfield]

What is the EC of you nutrient solution and what kind of water did you use ( tap water, RO water) ? If the pH drops on a daily basis after you fix it with pH UP solutions, then you might have a problem. But if normal for the pH to drop after the solution is prepared.

On my last grow I didn't bother raising it up from 5.2, as it didn't go below that value and the girls seems very happy till the end.

I recommend you to use Liquid Silicon as pH UP solution, because it is adding valuable minerals (Si) which are completely missing on a hydroponic grow.

When pH falls suddenly , try to add more water and dilute the nutrient solution to keep it more stable. This does not affect the feeding habits of the plants.

 

[yerboyblue]

Are the plants using water? Plants use water faster than nutrient. Less water in the system means the nutrient would be more concentrated, which may be what's causing such a fluctuation. Also, do you add water straight out of the tap to the system? I find my pH rises a little bit after letting tap water sit, I assume it has something to do with the chlorine breaking down.

I could be totally wrong about all of that. I am interested in the answer as well, I am just starting up with a hydro run and am new to it.

 

[farmari]

How much volume of a solution is there in total? How many watts of lighting?

 

[rajen]

What is the EC of you nutrient solution and what kind of water did you use ( tap water, RO water) ? If the pH drops on a daily basis after you fix it with pH UP solutions, then you might have a problem. But if normal for the pH to drop after the solution is prepared.

On my last grow I didn't bother raising it up from 5.2, as it didn't go below that value and the girls seems very happy till the end.

I recommend you to use Liquid Silicon as pH UP solution, because it is adding valuable minerals (Si) which are completely missing on a hydroponic grow.

When pH falls suddenly , try to add more water and dilute the nutrient solution to keep it more stable. This does not affect the feeding habits of the plants.

I switched back to tap water, the row didn´t work well. I had other issues with row.

And the ph was rising as the plants took lots of water in veg and early bloom.
Now its dropping, no matter what ec. (I started at 1.4 -1.5 ec, now I raised a little to 1.7)
I know that the ph is falling after some time when the solution is prepared. I start at 7.2 and it ends at 5.2 or so.
I also have a second res. with auto filling of the nute tank.
I only put tap water in the filling res, after some time it also drops from 7.2 to 5.7, without adding anything.
So i can exclude probs in my grow buckets.
As i wrote its 5 x 25 l and the nute tank of 70 l = arond 200 l all together.

I already use mineral magic which helped stabilizing the ph before, but isn´t any more effecting that good.

If I top with tap water out of the filling res. it won´t do much as this water is not treated, it´s pure tap water, after some time it drops to 5.7 - 5.8 ph which is my goal in the system,
The slh need about 5,8 at the beginning and then rising slowly during bloom, to end at 6.0 to 6.2, but that´s not possible like this.
Maybe i just add some ph+, and use less fert to stay at ec 1.8 in late flower. (those infos came from Green House).

I think 5.2 is too low, at least I have to have 5.8.
What causes the radical drop ?
It might be the dissolving of chlorides as the water stays in the tank.
I also added a rain forest bubbler to my fert. res. I´ll see if the ph rises again. I´ll keep u informed.
Thanx for the replies.!

P.S.: I uise a light rail and 400 W.

 

[Hydro-Soil]

Sounds like your tap water source varies... what's the weather been like for the last month?

Where does your tap water come from? Personally I use R/O because it's predictable in all locations... and I haven't stopped moving yet. My autism gets in the way of me 're-learnin' hydro with every new tap-water source or season change. LOL Saves me a heap of bruises on my forehead... ya know.

Stay Safe!

 

[farmari]

God knows what those additives might be doing. Could there be leftover additives at the bottom of the filling res when you fill it with only tap water? What's the EC of the tap water?
5.2 isn't necessarily too low. Looking at a chart, 5.8 is one of the worst places to be. A swing between 4.5 and 6.5 is good.
Try lowering the EC ...
a different type of nutrients might be more stable too...
I used to get really strange rapid PH declines in RDWC with GH Flora, but midflowering I changed to Ionic one part and the PH was very stable.

 

[rajen]

Thx for the answer.
As I´m growing greenhouse super lemon haze, I inquired what ec and ph and temperatures this strain needs. The ec should start at 1.2 and rise to 1.5 as a regular ec, at the end of flowering it should be 1.8.
In dwc it´s important to have a certain swing of ph from the lower end to the upper end (which is 6.1 ph to 5.7 ph. ) or vice versa.

I did some research for the Water Quality, my tap water comes from two different springs, and it´s switched from time to time.
What happend was, that I filled my res. for the automatic filling of the fert. tank with fresh water which was different in ec and ph, and different additives too.
This caused the sudden fall of ph.
I adjusted the solution in the system to 5.9 ph and 1.72. The fresh water autofilling tank is filled with tap water and ph + at ec 0.66 and ph 9.0.
When the ec rises and ph falls in the system it´s adjusted by the automatically added water from the filling res. when the plants drink. Like this it´s working fine.
I also don´t run rain forest bubble snakes any more, I adjusted a T at at the end of the air line, fixed it to the bucket. It makes al lot of surface movement which does two things, add oxygene to the water (far more than the bubblers, I believe) and keeps the solution in motion, all the small pieces of roots and dust is pumped through the drain tubes to the res. tank, where it's filtered before pumped through 4 mm tubes in each bucket (coming from a 13 mm feed line). The filter must be cleaned frequently but the water stays clear this way.

Hope I didn´t bore you ;-) I just wanted to share the solution of my probs.

 

[rajen]

update

update

I changed the whole solution, and now everything switched to what was normal....
it must have been a swing in the water quality from the community... and I thought I made a mistake on maintaining my System.
p.s.: thanx a lot to hydro-soil, u got the bulls eye!!!

 

[Hydro-Soil]

Glad I could help.
Track your variables... when something goes wrong, you'll have baselines to compare against. Deduction is the key.

I like the snake in the res idea... Thanks for that.

Stay Safe!

 

[rajen]

Well the snake works for one day, then it won´t let any air pass through.
I put more hole in them, but it then worked for another day or two.

What got me the succes were powerheads, they work fine and move the water, I bought 8 pieces for under 4 $ a piece, pretty cheap and so much worth it.
My recommondation for bubblers.
I asked in another thread how to install them (bottom, waterline....?)
I put them at the bottom pointing to the roots.
A plus is that all the rubbish is pushed towards the res. where it´s filtered before recirculating again.
If you have a super clear solution the snakes could work, but they don´t provide the watermovement you need, as a second try I just put them away and let the air just bubble out of a T-piece at the end, which was better then the snakes, but optimum ist the püowerhead. Give it a try, it´s cheap and you can see at first sight that it´s working better than anything I tried before.
I make some progress, after almost 30 years of growing I profit from you youngsters ;-)) in hydroponics ....biiiiig thanx for that guys, you´re the best !!
greez
rajen

btw. the slh builds up enormous resin, smells like lemon cake, and accelerates in bud build up at the end of flower, I was dissapointed for the size of buds, but now they start again....Harvest will be end of Feb. I´m lucky seeing forward to the results, I´ll keep u informed.!

P.S.: the fluctuation of ph is also a plus in knowledge I learned here...before I thougt they don´t like it, but as far as my experience goes....that´s the way to do it !!

 

[DHF]

In any fast hydro setup , as plants eat their juice , ppm`s drop and ph rises.....gradually.....so...

Dialage takes time......

Good luck....DHF..........

 

[rajen]

thanx, luck is always welcome
in my system a drop of ph an a rise of ec is normal right now.
I keep some tap water not ph-ed in refilling res, so when my girls drink more water (which drops ph) than nutes (which rises ec), the res. will fill up just as much as they drank with high ph and low ec, like this it works quite well.
I´m leaving town for a short holiday, and I try to adjust it so it´ll work without mantainance. My effort is to keep it as simple and mantainance free as possible. (once adjusted, which is for sure hard work ;-))

 

[rajen]

Update Bubblers and ph/ec

Update Bubblers and ph/ec

as I wrote before, I changed the rainforest bubble snakes to just T-pieces.
Then I changed to powerheads (a real recommondation!! works like hell).
But I left one bucket just with a T-Piece and this plant shows issues now, the leaves start getting yellowish with rusty spots on it.
No mites or anything.
I changed it to a power head today and will see ...
as I´m 3 weeks before harvest I don´t worry too much, the other plants look great and are instill increasing.
I, ll change to pure tap water the last week or so, I´ll keep u informed.

greez Rajen