Keeps My pH Dropping


A customer has a question and I hope we can get some opinions on it, thanks.

" I’ve grown hydo for about 7 years now and it seems your white widow cause my ph to drop over a few days, unlike most other strains I’ve ever grown. I use Advanced Nutrients Sensi-Grow and Bloom. Any ideas? Seems to be consistent as I’ve grown nearly 60 of your WWA."


What is he meaning precisely? at which stage is the plant? Is it during the germination ? what are the growing parameters and growing medium? Seedbank?


Nutrient hungry plants. Adjust accordingly. Unfortunately there are too many parameters left out to be able to provide even a ballpark of what’s going on.

How about filling this out and I’ll alert a couple of experts on hydro.

COPY/PASTE: This “Support Ticket” into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

Strain; Type, Bag seed, or NA

Soil in pots, Hydroponic, or Coco?

System type?

PH of runoff or solution in reservoir?

What is strength of nutrient mix? EC, or TDS

Indoor or Outdoor

Light system, size?
Temps; Day, Night

Humidity; Day, Night
Ventilation system; Yes, No, Size
AC, Humidifier, De-humidifier,

Co2; Yes, No
Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you smile

@garrigan65, @MacGyverStoner, @latewood


I have a few theories but would need ticket to determine causes


Strain; Type, Bag seed, or NA

Seeds are ILGM White Widow Auto

Soil in pots, Hydroponic, or Coco?
Grown in DWRC Hydro, been growing like this for 7 years.

System type?
Hydro tanks are 48qt coolers with air and recirculationg pumps.

PH of runoff or solution in reservoir?
I PH the water after adding nutes, I usually PH to 6.5 and let it fall.

What is strength of nutrient mix? EC, or TDS
Tap water is 145 TDS and young plants are abour 200-225 TDS
And larger flowering plants are typically around 250-275 TDS

Indoor or Outdoor
Indoor, Controlled Environment

Light system, size?
LED 300w x 4 lamps plus some CFL and T5 side lighting

Temps; Day, Night
Mid 70’s F. 24/7

Humidity; Day, Night
Ventilation system; Yes, No, Size
AC, Humidifier, De-humidifier,
I live in a dry climate, indoor Humidity typically around 40% up to 55%.
Inline Exhaust system through ceiling.

Co2; Yes, No
No Co2.

PH doesn’t seem to drop until the plants start to show flowers.
Seedling PH seems stable through first month.

I’ve grown hydro like this for 7 years, haven’t seen this problem before and is consistent
over 40 plus WWA plants.

I use Advanced Nutrients Sensi-Grow/Bloom two part.
My PH can drop a full point to a point and a half in a few days if left untended.
This happened a few times when I had to go out of town for a few days, resulted in losing several sun leaves that either yellowed and dropped or fried and curled.


This oddly enough is a very simple answer they are hungry some strains crave a a higher tds/ppm ph is stable so long as nutrients influencing ph are constant as your plant eats and drinks tds changes if they are eating lots they swing ph heavily I typically recommend tds/ppm of 600 or more the nutrients them selves become the stablizer

I am also quite fascinated by

the optimum ph in hydro is 5.8 but if it has worked for you for 7 years? what really can I say the few leaves you have lost are most likely result of the lower ppm/tds
Advanced nutrients also has gone almost exclusively auto ph’ing with their products so if you recently bought nutes check for a little phrase on it which says ph perfect technology.
If you went to their website you would also see ph recommendations for use 5.4-6.2
6.5 is most often a soil ph?

I can only offer suggestion if you feel it is strain specific issue than simply try my above advise set ppm 600+ and ph 5.8 see if they like it?


@peachfuzz @kabongster hey guys I work today could you give me a hand and offer some help and feed back on this issue I will be back on 9-10hrs form now and think @UVRay could benefit from a little minor adjustments :wink:


Fantastic! Thanks for the info. @UVRay I was wondering if either an increase in nutrients in solution or a change in the manufacturer could account for what you are seeing and I’d say BOTH!


the TDS numbers do seem extremely low from my little experience with AN nutes (pH perfect 3 way) and their recommendations…their values from the feed charts could exceed 2000 if used full strength, nearly multiplying the

by 10…

I can’t say anymore than what has been said

if it is pH perfect, adding pH balancers will only bump up the TDS

@Donaldj …maybe get …if Hydro: Water Temp? …added to the support ticket somewhere?..not that I believe it’s pertinent here, just thinking about it tho…


Thanks for the advice. No way can I run 600PPM in hydro, it fries the plants! Are you specifically talking about Deep Water Recirculation at 600ppm or soil, because I know for a fact I can run way more PPM in soil than hydro. No matter what strain I’ve grown in the past I could never run higher than 400PPM without burning the plant and I’ve used Fox Farms, Botanicare and AN Sensi over the years…

The fan leaves yellowing and curling was no doubt from the dramatic drop in PH causing nute lockout and not a lack of nutes. The effected leaf stems go red when this happens too.

I will try gradually raising the PPM/TDS as see if that helps.

I have about 30 WWA plants growing now, and 4 of Robert’s Gold Leaf Fems. The Gold Leafs are only a few weeks old so I’m not expecting nor experiencing a fast ph drop at this stage. If the issue is strain specific I’d expect to not see fast ph drops in the Gold Leaf.

No matter what nutes I’m using, I can’t understand why the ph can fall so low so fast. I have never seen this issue over my 7 years of growing indoor hydro.

I’m using AN Sensi/Grow 2 part and then once flowering begins I start mixing in Sensi/Bloom. Same process I’ve used the last 3 years since dropping Botanicare for AN.

I’ll update as probe farther into this. I really hope it’s as simple as raising my nute percentage. They grow plenty fast now, easily harvest ready from seed in 90 days.


Do the bottles have “pH Perfect” on them?

what is the pH of the nutrient solution after you mix it, before adjusting to 6.5?

the TDS for your tap water isn’t too high at 145 tho it could matter what’s in your water for dissolved salts

I have done a couple of DWC hydro grows and during flower had no leaf problems from a ppm as high as 1700 (one week only), tho not a number to be maintained all thru flowering.


I’m not a fan of (AN) nutrients , especially for hydro dwc or nft…
After my clones are rooted , I start nutrients around 300 to 500 ppm and for heavy veg 500 to 800 ppm…
Flowering ppm starts at 800 and increases to 1400 gradually… I don’t grow auto’s , so I can’t help you there… :wink:

:v: :sunglasses: