PH Keeps Dropping

[dogstick]

Hey guys and gals. I have been having an issue with my girls. I have 4 in a scrog with a 15 gallon res. They are super happy both up top and below but for some reason the ph keeps dropping like mad. I just changed my res and lowered the concentration of the nutes and what do you know it is still dropping. The ppm's may go up a little but not that much while the ph just keeps drifting dwn. I just keep adding ph up and also wondering if I keep putting the up in will that harm my girls. Have any of you experienced this before? I am kinda clueless on what to do, havent had this problem before but want to get the ph dialed in. Thanks for any help you guys can dish out.

 

[PrairiePoet]

Hey Dogstick,

Need some more info. How are you growing, what nutes, where in the grow time are you, over what time frame and how much does the pH drop.

pH should drop daily by a little. Enough that you should be adjusting it every second to third day. Also, a lot of people just get overboard on checking stuff. Someone here posted once that you can check pH fifty times and get fifty different readings.

Prairie

 

[Xlr8]

Agreed that a little more info would help, but I'm guessing your mid-late flowering cycle. Usually that's when I experience this sort of PH drop. I let it drift down and try not to over-manage it too much, but I do correct it every other day or so to keep it in-line.

For me, I have to correct PH down in Veg and earlier stages, and correct PH up as I get into mid and later flowering.

That's just my experience - good luck to you!

 

[dogstick]

Thanks guys for your input. I am running GH 2 part series and am onlylittle past 2 weeks in 12/12. You guys are right about the ph rasing in veg and dropping in flowering but I am experienceing a ph drop of 1.0+ at least a day. I am now running a weaker strength nute regime so I am seeing if that helps. The past grows I have been running 5 plants but now 4 and those 4 drink more than the 5 did due to more lighting I reckon. I check it so often cause it can easily slip under 5.4 if I don't. I will post if I notice a difference in this new nute batch. Thanks again for your time and effort.

 

[HB Rob]

If the pH drops after a rez change then the plants are taking in more water than nutrients. Wouldn't it make sense to pH the rez at 5.8 initially and top off with plain water between changes to keep pH stable?

That's my take on the situation, but I don't run hydro.

 

[Xlr8]

Normally I shoot for 5.5-5.6 as optimum in hydro. When I'm in situations where PH is dropping, I shoot for 5.8 (knowing it will drop) and will let it drift down to 5.2 or so before correcting - but that's just me, others may do this differently.

I think adjusting nutrient strength as an experiment might be good too (as you are doing).

Personally I wouldn't sweat the movement too much. It's a pain making daily adjustments, but I've not had it be detrimental. I used to over-manage this, but I don't sweat it as much anymore.

Oh and the more I think about it - it's not mid to late flowering for me that I experience this - it's actually earlier on in flowering (like where you're at here). Having said that I think it will improve some on it's own over time too. I just remember this comes up for me for a couple weeks each grow in flower.

Rob - I think what you're saying makes sense as well, but probably an extra step not necessary unless it's just too maddening making a daily adjustment.

Just my 2 cents worth - Best of luck with your grow!!

 

[dogstick]

It seems to be holding a little better after the res change. So if that was the case then it was too strong of nutes since they are drinking so much more now a days.

Rob- After I change my res it always rises but only now have I been dealing with such ph drops. I think it will pan out with the weaker nute strength.
Thanks you guys for your input. I will post back when I know for sure that its chilled out.

 

[WillyBudz]

Didn't know GH had a 2 part hydro, Have you tried GH 3 part w/o the grow aka Lucas formula?

I use per gallon:

For Veg:
5ml micro
10ml bloom


For flowering:
8ml GH micro
15ml GH bloom
5ml GH KoolBloom
... variant on Lucas found below. Never have had a ph issue using it. Try the advanced version 1/2 way down if you keep having issues. After you get used to it you can tinker and tweek it to your specific grow.

General Hydroponics Flora Series Feeding Strategy - Lucas Formula

G-M-B (Grow-Micro-Bloom)
0-5-10 - For Vegetative cycle (18/6)
0-8-16 - For Flowering cycle (12/12)

The numbers above indicate the number of milliliters (ml) of Flora Grow, Micro or Bloom formulas that I use in one gallon (US Liquid) of nutrients.

You will notice I dont use any of the Flora “Grow” formula, do not need to, the Flora "Micro" provides plenty of Nitrogen.

There are two ways to work with this formula:

1. Top off the reservoir daily using a pH corrected water solution as required to maintain full reservoir level. After adding back an amount of water equal to the amount of your reservoir capacity you should change the reservoir and put in fresh solution.

2. Top off the reservoir daily using a pH corrected 100% strength nutrient solution as required to maintain full reservoir level. Continue to use this nutrient solution without dumping the tank unless the PPM rises above acceptable levels.

Between vegetative and flowering cycles you should dump your nutrients, then flush (possibly with Clearex) to remove salt buildups, then change to the other feeding program. Always shake your GH nutrient bottles before using them!

For young plants, just transplanted into the hydro setup, give them 50% strength nutrient mix to prevent overfeeding them while their young. Gradually bring up the mix to full strength as they grow over the next few weeks or so.

The lucas formula is normally intended for use with RO or near 0 PPM water.

NOTE: The Lucas formula eliminates the need for Epsom salts to correct (Magnesium) Mg deficiencies in most normal feeding programs recommended by manufacturers. Cannabis needs a lot of Magnesium to thrive.

The Flora Micro is providing the Nitrogen and the Magnesium in the proper balance, thus there is no need for the Grow formula and little or no room under the maximum acceptable ppm limit of 1600 @ 0.7 conversion.

Calculated EC/TDS levels:

EC microsiemen:
0-4-8: 946 µS
0-5-10: 1184 µS
0-8-16: 1894 µS

TDS @ 0.5 conversion:
0-4-8 = 473 ppm
0-5-10 = 592 ppm
0-8-16 = 947 ppm

TDS @ 0.7 conversion:
0-4-8 = 663 ppm
0-5-10 = 829 ppm
0-8-16 = 1326 ppm

Addback Calculator - (For Advanced Users)

Say you were running the 0-8-16 formula, at 0.7 conversion with a 22 gallon res. When you first fill it up, your ppm will be around 1330.

Now you have been growing for a week, and some of the water has been taken up by the plants, some has evaporated, and now your res is at 947 ppm. You need to get your ppm from 947 to 1330. Here is the equation:

((target - current) / target) * 8 ml per gallon * res gallons = Flora Micro (ml) double this figure to get Flora Bloom (ml)

Example:

((1330 - 947) / 1330) * 8 * 22
(383 / 1330) * 8 * 22
0.3 * 8 * 22 = 53 ml Flora Micro

53 ml Flora Micro, double that and you get 106 ml Flora Bloom. So 53 ml Flora Micro and 106 ml Flora Bloom to add back to your 22 gallon res to get you from 947 to 1330.

 

[dogstick]

Good info willy. I have used the 3-part series before but wanted to give the nova a shot. I am on the 4th harvey with it and like it but it is messy. I have been thinking about the lucus formula. It seems like you could save a lot on nutes and get great results. How long have you been using that Formula for?

 

[PetFlora]

I agree with XLR8. I find pH rises in veg and drops in flower.

hth

 

[dogstick]

Thanks everyone for input! It turned out to be just too strong of nute solution. Last go arounds I have had 5 in my room and now dwn to 4. 5 was too much for 3'11 by 3'11 room and now that I have 4 they are all getting much more light and there for drinking much more water than the last batches causing the ph to swing like crazy. I lowered the nute solution and it is back to being stable. The 4 girls are drinking over 2 gallons a day. Thanks again for your help guys

 

[Xlr8]

Thanks everyone for input! It turned out to be just too strong of nute solution. Last go arounds I have had 5 in my room and now dwn to 4. 5 was too much for 3'11 by 3'11 room and now that I have 4 they are all getting much more light and there for drinking much more water than the last batches causing the ph to swing like crazy. I lowered the nute solution and it is back to being stable. The 4 girls are drinking over 2 gallons a day. Thanks again for your help guys

Glad you got it figured out. 2 gallons a day for 4 plants - now that's some thirsty plants!!

 

[Motherhugger]

Yeah, sometimes you need to add fewer nutes in order to get things to work.

I don't run GH, but I've found with AN is that I need to add 25% less at first since doing anything more makes the grow freak out.

Good luck with your grow!

 

[dogstick]

I was giving them not even half the recomended amount with still huge ph swings. I think it came dwn to the water consumption with the small res.

 

[monkeybudz]

I just started to use X Nutrients and notice during the day my ph drops a lot!
What I was used to with GH was my PH rising often.
It's only 3 days before I will switch to to 12 hours for flowering. For the life of me, I don't know why my ph is dropping so much. This has never happened before.
I have used PH up- which I've not used before. I don't want to have plant issues. although I notice they look much happier then yesterday- so perhaps they are absorbing what they need- yet my experience with other products usually raises the PH
This time it's dropping quite significantly.
This morning I drained 1/4 of the water out and added normal water which has a neutral ph of 7. two hours later, the ph was back down.

Any input would be appreciated