Need help with rising Ph....!

I've got a bit of a dilemma...! I now have 12 plants in bloom, 3 sets of 4, spaced out by 1 week. My problem is rising Ph. My water that comes into the grow area goes thru a cylindrical water filter, one you use for water going to a refrigerator. From there it goes to a 50 gallon reservior that is aerated and constantly moving. The water comes in at 7.8-8.0 Ph and 80-180ppm. I'm using GH FloraNova products that after mixing brings that water to 5.8-6.0 Ph and 1200-1400ppm. I run the pump for 15 mins, 1hr before and at lights on. After that the pump runs for 15 mins. every hour til lights out, then one time in the middle of the night. After 1 full day the Ph rises from 5.8 to 7.2. It takes me about 1/2 teaspoon, per 6 gallons of nutrient solution, to lower it back to 5.5-6.0.

The reason this is worrying me is that there seems to be a nutrient lockout. The plants that are almost at 1 month flowering have been losing their fan leaves from the bottom and moving upwards. It seems to me that I have a Nitrogen deficiency because of the yellowing older leaves along with slightly red stems. Please let me know what you think. Other then the yellowing fan leaves the plants are budding and filling out nicely.

Well you definitely have some problems. The water that comes in, what PH is it? ...I think I would start eliminating possible causes, and I would start with removing that filter. Do you have any metal lines that the nutrients run in? Have you checked the accuracy of your ph meter?

keylime

@ Keylime. Thanks for stopping by!! Water comes from tap, thru 1/4" drip line, thru the described filter(not problem IMO), no metal lines near nutrient fluid and lastly I calibrate meter once a month 7.0 and 4.01. Meter is a Hanna pH/EC/ppm meter.


What is your experience level? Experienced novice

What type of hydro set-up are you running? Recirculating drip system

Your Equipment:
A) Type and wattage of lights. HPS in Bloom, MH in Veg.
B) Distance from tops? 6â?�-12â?�
C) Reflector type? Enclosed reflector/ vented
D) What are the bulb wattages, kelvin ratings, and schedule?
Veg.- 400w MH 19on/5off
Bloom- 600w HPS 12on/off (also have a 400w HPS thatâ??s not on yet, both are on a mover)
E) Is there a consistent fresh air supply? Yes
F) Do you have an exhaust fan and a circulation fan? Yes
G) Size of reservoir? 18 gal total, 8-10 gal used
H) What medium if applicable. Hydroton w/rockwool

Your nutrients and water:
I) If using rockwool for clones or seedlings, did you rinse the cubes well, with properly ph'd water? Yes
J) Source of water. Tap What's it's ph? 8.0-8.4
K) Specific brand and N-P-K ratio for each bottle. List dosages (quantity per gallon) and current feeding schedule.
GH FloraNova system
Veg.-GH/FN Grow(1tsp per Gal) and Flouralicious Grow(1/2 tsp per Gal) 1000-1200ppm
Feeding- DWC/constant aerated
Bloom- GH/FN Bloom(1tsp per Gal), Flouralicious Bloom(1/2tsp per Gal), Liquid Kool bloom(1/4tsp per Gal) and Dry Kool bloom(Not used yet) 1100-1350ppm
Feeding- 15 min. intervals every hour starting 1 hour before lights on and conâ??t thru lights on, once during lights out
L) What is the ec/ppm of your unadjusted tap (or filtered) water? 70-170ppm
M) What is the ec/ppm of your nutrient solution? 1000-1350ppm
N) What is the temperature of your nutrient solution? (reservoir high and low temps) 72-76 F
O) Does your ec/ppm show a rise or fall when you do your daily PPM check? Slightly raises
P) Does the ph fluctuate? Yes, from 5.6 to 7.0 in 24hours
Q) Do you foliar feed? If so, with what, how often, and at what time do you
spray? (Just after lights come on, just before they go out...) No
R) How often do you replace reservoir water/nutes? What does it look like before changes? (clear, foamy, green, brown...) Every 5-7 days, tan tinted clear with some sediment

Your growroom:
S) What size of closet, room or hut? 10â??x2â??x8â?? bloom area 10'x2'x8' veg area
T) What are the temps and humidity levels while lights are on? ...With lights off? 85/60% on, 75/65% off
U) Have you seen signs of insects in the growroom? Yes, fungus gnats
V) Are the roots long and white, or brown and slimy? Long and white healthy looking

Your strain:
W) What strain are you growing? Nirvana AK-48 and NL#5xHaze
X) From seeds or clones? AK-48â??s are clones from seed, NL#5xHaze clones from dispensaryâ?¦.reason for the Fâ??ng GNATS!!!
Y) Is this an autoflower strain? No, photo-period

In bloom, Iâ??m having problems with yellowing lower leaves and reddening stems. I also think the buds should be a bit further along/filling out better. Iâ??m thinking Nitrogen deficiency, probably from pH fluctuations or maybe nutrient lock-up!? All leaves close to buds are nice and green but the fan leaves at the major intersections are the ones affected. Iâ??m not ruling out the Fâ??n GNATS but my roots look healthy/white/searchingâ?¦ HELP the first 4 plants in flower have been there almost a full month. These are the plants showing the worst problems.

Please, any help/advice is greatly apperciated!! :jointsmile::hippy:

could you plz list the N-P-K of both the grow and bloom?? I run GH 3-part and just change the mix I was using and what a difference when a touch more of N does. BTW if you have not picked through Latewood's Legacy at top of page you might take a peek. He is using GH 3_part but the principle behind it all makes allot of sence :thumbsup:

the number one reason why anyone has a nitrogen def is because there's not enough N in the fert mix. Adding fert to water gets the ppm to raise and the pH to drop. If you're seeing yellowing lower leaves the number one reason why this happens is because of a lack of nitrogen. I think you need to raise your ppm to 1500 and check this a pH more frequently if you can. It sounds like your ppm is too low to begin with and it's probably lowering rather quickly as your pH rises. If this is the case then I think it's your ppm, not pH, that's the issue. When you put that together with yellowing lower leaves, which indicates a need to nitrogen, then I'd say they are eating alot. You can either raise ppm to 1500 and see if you get better stability, or check 1300 more frequently and keep it there the best you can. But this means you have to be available to check the ppm alot. If you can't do this, then I'd raise the ppm to 1500 or so and see what happens. Another issue is the time factor. You can try 1300 or so and run pump for half hour every hour or try more than just once after lightsout. Or mix it up - 1500 with longer run during daytime and only once at night. You have a little more control with the time factor in a reservior system, so try more frequent runs.

Do not increase your ppm right now. You stated that ppm rises at the moment. This means she is drinking more water than nutrients, so you should be fine there.

I am assuming that you have had this ph problem from the beginning.
If that is the case, did you soak and adjust the ph of the Hydroton? (Took me three days of soaking and changing water to get it down and stabilized.)
If not this is most likely your cause of the rising ph. Hydroton comes with a high ph that should be adjusted down before use.

Mimbrisvalleys posts on Ph and why it rises and falls, rising Ph is NOT a bad thing. actually he posted links to a study

Daddy

Thanks everybody for ur input! Lastnight I soaked all my bloomers in warm water to drown out a bunch of fungus gnats while I cleaned the tray, reservoir, pump and bubblers. What a mess!!! Never again will I get clones from a dispensary!!! Tons of Gnats...I understand I can't kill them all by flushing but at least there are a lot less of them. Refilled reservoir w/ ~8gal filtered water 7.6pH 210ppm. The nutrients I added were 6tsp GH/FN Bloom, 4tsp Floralicious Bloom and 2tsp liqiud KB, bringing the solution to 6.4pH and 780ppm. I checked my pH at lights on and pH is at 6.9, less then 24hrs after refill. I also installed my CO2 emitter, it's on a controller, like I needed to add anything more to the equation/problem!?!

@tinytoon, I'm honored you're droppin by to lend a hand.
Veg.-GH/FN Grow:7-4-10 and Floralicious Grow:1-0.7-0.6
Bloom GH/FN Bloom:4-8-7, Floralicious Bloom:1-1-1, Liquid Koolbloom:0-10-10 and I have but have not used yet Dry Koolbloom:2-45-28. Also, I use EarthJuice's Natural up/down(more down then up).

@polish, Thanks for the info. I agree with you that there's a nitrogen deficency and looking at the plants tonight I'm thinking they're deficent in all the primary elements. Maybe from the soak? But I just bumped them up from 720ppm to 1250ppm, I also added 1tsp of GH grow form 3part GH. I'm not sure if I want to up the pump intervals or the ppm? Root growth is good and healthy so I know they're not drying out. I don't want to drown them, in the containers I have corners of rock wool cubes in layers. I fill the containers in this order(I use a 3"net pot for scoop) 2scoops hydroton, 4 corners of rock wool, 2scoops hydroton, 4 corners RW , 2scoops hydroton, insert clone in 3" net pot and fill around pot w/ hydroton. I feel the rock wool is keeping the plants from drying out, IMO. Going up to 1500ppm sounds kinda high, but you never know til you try, right?!

@tikiroom: You bring up some good points! No, I'm not going over 1350ppm for right now and again, no, I didn't presoak my hydroton......and that makes a whole lot of sense!!! I will, from now on, presoak my hydroton! I don't know if you've ever experienced this, but I notice I get this white stuff floating around in the water after adding pH down and letting it sit. Any ideas?

@D.No$: Thanks for pointing me in a good direction.

I will have pictures up here and my grow log tomorrow. Check out my grow it's Nirvana AK48 seed to weed!! I think my problems are coming from this rising pH dilema. I've read that you dont want big fluctuations in ph over short periods of time. What's worse leaving pH at 6.9 or dropping to 5.8-6.0 everyday from 6.9? To get that drop I use about 3/8 to 1/2tsp of down for 8gal of solution. I've been changing solution every 5-7 days adding about 3/4 gal filtered water everyday for 12 plants. Again thank you every one who have stopped by with your words of wisdom and experience!

If you have yellowing lower leaves, your plant isn't getting enough N. I don't know if I would use that high phosphorus bloom fert. I think that kind of thing you just use one at the beginning of flower cycle and not again. Sometimes pH rising alot in hydro. I did a DWC once and I went to bed after lowering the ph to 5.8 and it was 6.7 in the morning. I couldn't figure it out but came to the conclusion that fighting it was a waste of time. I'd focus a little more on the nutrient issue, making sure they get enough ppm and it makes sense that if you run the cycle longer or twice every 15 minutes, this might actually solve the yellowing without adding much in the way of fert. If the plants are really hungry they'll take up the fert rapidly and this will also cause your pH to rise as a rising pH usually means lower nutes in the water. I don't understand how your ppm can slightly raise is you don't add any.

One other thing I just noticed is you keep mentioning filtered water. Some filters actually add sodium to the water, plants do not like extra sodium.
If this is the case it could explain the yellowing of the leaves, but not the rising ph. I do believe the ph is from the hydroton.
Maybe try using just regular tap water, give it a week and see what happens.

That's just my :twocents:

Best of luck to ya. :hippy:

Hey guys I know this is probably a dumb question but does the pH of R/O water rise as it sits out over a few days as do other waters? I'm curious as to if i should worry about that happening or not.

Help is very much appreciated, Thanks! :i feel stupid: