Strange EC behavior. Dont know where to post. Help!

[Jimmy Joe James]

Hey Everyone!
Its been a while since I posted since Ive been traveling all over the place. But I finally landed in AZ, where recreational is now legal and I can legally grow without worrying like in Puerto Rico lol (and YAY!)

AnywaY Ive been re learning now with growing in a COMPLETELY different environment ( dry scorching desert vs extremely humid tropical island). Its been an eye opening experience and I have learned a lot from growing in such different environments. However this issue stomps me and its not necessarily bad because the plants havent stopped growing. They’ve been taking it like nothing.

I decided to plant an Old LSD-25 seed i had lying around and a Dutch Passion Blackberry Kush. At the moment LSD is in week 4 and Blackberry Kush at 3 weeks. They’re both showing similar issues. I woke up to see them fine and i checked the PH and ec as routine. These were the measurements the night before.

LSD-25 (week 4 = EC .750 ph 5.4)
Blackberry Kush (week 3 = EC 0.700, PH 5.6)

Nutrients Advanced Nutrients 3 Part and hydroguard in DWC buckets.
The next day I woke up to the following.

LSD-25 = EC 0.820, PH 5.1
Blackberry Kush = EC 0.820 PH 5.6

Both were missing about half a gallon of water but no signs of nute burn or deficiencies. Naturally I though the plants drank more than they ate and i was about to put RO water to makeup for the rise in numbers. Here’s where it starts to get weird for me.

A friend called me with an emergency and I just bolted and left the plants without pouring the water. Left them like that for about 2-3 hours when I finished helping my friend i came back with both plants with burnt tips. I thought that was normal becuase of the time i left them unattended. I decide to measure before adding water to see what the damage is and if its just better to change the rez. Heres what i found after 3 hours:

LSD-25 = EC 0.588 PH 5.4 no water level drop after 3 hours

Blackberry Kush = EC 0.650 PH 5.6 also no water level drop after hours.

I double check and triple check. So I decide to play it safe and get them back to the original EC’s of the night before to play it safe (.750 and 0.7)

The next day a gallon of water is missing and they both a 0.9 and 0.8 with the LSD plant now showing a cal mag deficiency. For the hell of it i decide to wait 3 hours and as expectec the EC of both plants took a nose dive to 0.5 and 0.688 and had to add nutrients again. What am I missing? Im increasing the cal mag and the nutes but these two are behaving in a way ive never seen in hydro before. Again they’re still growing fine temps at 80f and humidity at 42%. Heres some pics, anybody have any theories?
I usually use Med Man’s method posted here on the forums but instead of starting seedlings at 0.2. I started at 0.5 cuz tbh was trying to stunt them a little cuz every time I use Med Mans method they outgrow the freaking tents and become beast that i cant handle. But I can safely say that hasnt worked these plants havent cared at all

 

[Mañ'O'Green]

Hi @Jimmy Joe James Looks like you might be headed toward a lock-out? But first I want to talk about your PH. IMPE It is too low for DWC. 5.8 is the target with the spread 5.5 to 6.5. I personally run 5.6 to 6.2 just in case I slip there is a cushion factor.

Now for nutrients, What are you using and how much, what is the source of your water? What is the reservoir temp? Jeez I am needy

 

[Wian]

Jeez I am needy

Hahaha!

Following to learn..
As a non-expert.. if my PH drops in DWC I start worrying about the roots. Normally when healthy growth occurs the PH goes up for me.

 

[Jimmy Joe James]

Hi @Jimmy Joe James Looks like you might be headed toward a lock-out? But first I want to talk about your PH. IMPE It is too low for DWC. 5.8 is the target with the spread 5.5 to 6.5. I personally run 5.6 to 6.2 just in case I slip there is a cushion factor.

Now for nutrients, What are you using and how much, what is the source of your water? What is the reservoir temp? Jeez I am needy

Im using Advanced nutrients 3 part. The Ph is swinging all the time from 5.2 to 6.2 throughout the day (usually in the low 5’s in the morning and enthering the 6 ranges a couple of hours before lights off. Im guessing its that ph perfect. I have 4 plants and only two have these symptoms. I just checked lsd again and the EC was down to 0.550 but topped it off again to .840 cuz its finally starting to flower. And Im using RO water with just 30ppm. Maybe i started a little high i didnt want them to get too big this time. But like i said they just keep growing like nothing. I added more cal mag but the EC keeps going up and down every now and then.

 

[Jimmy Joe James]

Also rez temp is at 72f

 

[Mañ'O'Green]

I think something is wrong because the PH is getting too low. Have you calibrated the PH pen recently?

 

[Jaydot]

Hey bud,

I've learned that RO water has no adequate bi-carbonates to stabilize pH levels, something about the ppm being too low.
There's a whole scientific explanation but I'm just a simple man, basically you need between 60 and 100 ppm for this.
So maybe consider looking into that regarding the PH fluctuations? Just my two cents : )

Plants look great though, maybe that one is or was a bit hungry for magnesium because of PH fluctuations, but I know nothing about hydro.
Good luck.

 

[Jimmy Joe James]

This is my 3rd grow with Advanced Nutrients 3 part. I only use 3 part and hydroguard during Veg. I have calibrated ph pens i even opened i new one unused i had in storage for this case. But ever since switching to Advanced from GH i honestly check the PH once a day to monitor the chelates. I stopped monitoring the PH too much cuz i noticed that even if goes to 6.6-7.0 plants dont seem to mind (unlike in GH which is meant trouble. But That PH perfect has that ph swinging wildly every day. So i ignore it since i change the rez every 8 days anyway while the chelates it has to regulate the PH lose their strength. This is honestly the first in 3 Advanced Nutrients grows that i have this issue. I never had this issue with GH but i was battling with the ph 3 times a day with GH. This has been a more set and forget and i have learned to not stress myself with the swings as the plants have seemed to like it so far.

 

[Jimmy Joe James]

I might have found the issue guys. I havent changed my membrane of mu RO filter in 5 months and i checked and the water comes out at 150ppm but the nutes say thats too much. Went out bought a new RO membrane and currently making a fresh batch of nutes for the plants and do a full rez change see if thats the issue. I’ll keep you guys posted and thanks again @Mañ'O'Green !!! Once u said ph issue i started researching on it! The 3 part nutes with PH perfect apparently are very picky with the water if this turns out to be the issue.

 

[Jimmy Joe James]

Hey bud,

I've learned that RO water has no adequate bi-carbonates to stabilize pH levels, something about the ppm being too low.
There's a whole scientific explanation but I'm just a simple man, basically you need between 60 and 100 ppm for this.
So maybe consider looking into that regarding the PH fluctuations? Just my two cents : )

Plants look great though, maybe that one is or was a bit hungry for magnesium because of PH fluctuations, but I know nothing about hydro.
Good luck.

Thanks guys! I think youre right, so far the ph has stayed at 5.8 with new RO water and membrane replaced. Water nows back to around 5ppm with the new membrane. I think unlike their sensi line, AN 3 part MGB is more sensitive with the water ppms. So far the ph stays at 5.8 and the plants just keep growing like nothing happened. Hopefully i can keep the size of the plants down this time lol. I struggle too much with the plants hitting the lights most of the time.