PH Issue Sudden drop!

Hey Guys,

Tried to search for anything like this and came up with nothing.

I had some issue with my PH rising at first, and that I have gotten past by using bottled water. PH was stable for almost 2 weeks at 5.5- 5.8.
I am running RDWC, water never goes over 70 running 1/3 recommended nutes for seedlings (found the nutes helped keep the PH steady as well) no longer seedlings but I want to start working my way up to full nutes slowly.

Yesterday for some reason my PH on 2 out of three droped to 4.1- 4.2 , not sure if its the strain that did it, as both that dropped are Automara II and the other that was still stable at 5.8 is a Sensi Star.
I did a water change right away as a PH of 4 will hurt for sure im guessing, but it makes me think this could be something else as the day before everything was stable at 5.7-5.8. Even when I was fighting the rising PH it never jumped that much, a .5 to 1.5 at most per day, so for it to drop almost 2.0 in a 12-18 hour period is scaring me.

This was the first time I have seen a drop in PH and a large one at that, normally its an adjustment down every so often.

Oh and I change my water weekly as well. Plant looks healthy, even when the PH was at 4.1 you would not know looking at the plant as its growing like a weed! hehe

Checked the PH today and its up again to 6.0 from the 5.7 I had it at right after the water change.

Also being new to this, how much of a roll does temp have on PH? for example my water was 72 from sitting in the non AC room all day before I did the water change, and now after a day in the room its at 68, would that be part of the rise again to 6.0? not a big deal a slow rise is normal, just wondering if I need to ensure my water is the right temp before I start nuting, PHing etc.

please if anyone has any insite or things I need to check let me know, and if you need more information I will gladly provide!

Here is a couple pictures, everyone likes pics! Middle of the three top picks is the Sensi Star

Temperature does play a role, but a very tiny minimal one. Look on your buffer bottle and they'll have a temperature chart. Say 20C 7.01 buffer should read 7.01. At 30C it should read 7.00

I pulled these numbers out of my ass, but they work like that and are close to that. The difference is small as you can see.

I've had my PH go down like that before. I think it was because the night before when I PHed down I must of added too much and my meter didnt read that quickly, so it said 5.8, but was really a falling 5.8 that my meter would have picked up had I left it in longer than a few steady seconds at a 5.8 reading.

I wouldn't worry, if it raises a lot then worry as it could be a bacteria problem.

And no it won't hurt the plant. Left like that yes it will, but overnight no way man. PH is only relevant for nutrient uptake. Plants do store nutrients within themselves, so if it couldn't get any from the water at 4.0(which it wont) it'd use its reserves. Now if you kept it at 4.0 it would show every deficiency under the sun. In fact I think manganese and iron are the only things available at that PH.

firsttimeARE said:

Temperature does play a role, but a very tiny minimal one. Look on your buffer bottle and they'll have a temperature chart. Say 20C 7.01 buffer should read 7.01. At 30C it should read 7.00

I pulled these numbers out of my ass, but they work like that and are close to that. The difference is small as you can see.

I've had my PH go down like that before. I think it was because the night before when I PHed down I must of added too much and my meter didnt read that quickly, so it said 5.8, but was really a falling 5.8 that my meter would have picked up had I left it in longer than a few steady seconds at a 5.8 reading.

I wouldn't worry, if it raises a lot then worry as it could be a bacteria problem.

And no it won't hurt the plant. Left like that yes it will, but overnight no way man. PH is only relevant for nutrient uptake. Plants do store nutrients within themselves, so if it couldn't get any from the water at 4.0(which it wont) it'd use its reserves. Now if you kept it at 4.0 it would show every deficiency under the sun. In fact I think manganese and iron are the only things available at that PH.

Click to expand...

Unless the nutes use chetlets(sp)? or how every you spell them to allow specific nutrients at wider range of ph levels.

I know slime/rot and other pathogens in the root zone can also wack the ph in many ways.. so just make sure you're fighting the right cause to stop it.

Update.

So far back to a normal .1 to .2 rise per day. No clue what caused the sudden drop but i caught it and it does not appear to be ongoing.

I treat every water change with 2.5ml %29 H2O2 per 15L of water, not sure if thats strong or weak, but being doing it since I started to make sure I dont get any root issues. I know they can still happen but I figure if I go proactivly on it I should avoid the issue. My water temps are under 70 at all times too, so this is another plus from what I understand.

I had a look at my PH down and up (should have done that first! dam stoner) for any temp stuff and nothing on the bottle at all about it. not sure this matters much as temps are stable anyway, just going to keep the water in the ac room so if i do need to do a water change due to water issues right away I have water the right temp when adjusting and preping it.

Sorry if this seems trivial, just want my ladies to turn out good!

oh and I topped the largest Automara II, left the other, not sure how the auto flower will respond to topping, as I have heard other strains of auto didnt react well to it. This way I have one to compare any differences with.

Are you certain your meter is working well? cn

Yep have a tri meter, 3 weks old, even took it back to make sure it was calibrated correctly just over a week ago, I also checked with the drop kit i have when i seen it that low and color looked right for 4.0-4.5
I started with the drop kit, but between the grow light, house lights and sun light its a different shade!!! drove me nuts enough to go spend $200 on a meter!

I have a tri-meter and it's OK but the settings on mine are not stable. I also have an Oakton handheld, and I like it way better. cn

StealthOne said:

I treat every water change with 2.5ml %29 H2O2 per 15L of water, not sure if thats strong or weak, but being doing it since I started to make sure I dont get any root issues. I know they can still happen but I figure if I go proactivly on it I should avoid the issue. My water temps are under 70 at all times too, so this is another plus from what I understand.

Click to expand...

With 29% you can use up to 2ml/L so yeah you're a bit weak on it. Thats what ABF recommends for flood tables. I used it for a little bit in DWC at that dosage and never hurt any. I now use nothing and my water is 72F and my roots look fine. No slime. No rot. Slight yellow from air exposure, but healthy enough. I just change my water every week, though sometimes I get 2 weeks out of the buckets with nute top offs in between.

StealthOne said:

I had a look at my PH down and up (should have done that first! dam stoner) for any temp stuff and nothing on the bottle at all about it. not sure this matters much as temps are stable anyway, just going to keep the water in the ac room so if i do need to do a water change due to water issues right away I have water the right temp when adjusting and preping it.

Click to expand...

PH buffers have it on them not up/down. And it is a bit over kill. I just take bucket and fill up with the spiket in the room and the waters cold coming out about 60F, but it warms up to about 72F eventually so no problem there.