PH problem! Uncontrollable! Please help :(

[bendoslendo]

2 plants from clone, each in 5 gal DWC suspended in netpot with expanded clay. Using Lucas formula for veg.

This problem began a few weeks ago in veg and I've been fighting it since. The leaves developed tiny brown spots which turned into big spots which turned into entire leaves dieing. pH problem right?

My pH is very low around 4. It drops within a day after adding nutes. Last night I flushed out my buckets with several gallons of plain tap with a ph of ~7.5 and filled the reservoirs up with it. Today I check it and its back down to around 4 again! The nute solution is cloudy.

The plant is still growing, but i think its someone stunted. I've been changing or adjusting the solution every day? What am I doing wrong?
This photo is from the problem first stated appearing. It has gotten much worse since, with all of old growth affected and dieing.

 

[lysol]

looks like it to me, whats your ec / ppm? more nutes = lower PH, less nutes = higher PH, how big is rez? cloudy nutes = dump and refill. read up on nutrient precipitation on the flairform link in my sig

 

[Ms_Weekend]

Dont flush with 7.5!.....5.8-6 is what it needs all the time......little more info on ppm or ec? what kind of nutes? 3 part? not familiar with lucas never used them....how are you measuring ph? ec?

 

[bendoslendo]

I don't have a TDS/EC meter yet. I know I need to get one. This is my 2nd grow with this set up and I had a similar problem at the end of my last grow.

They were getting GH 3 part, but only 5mL micro 10mL bloom per gallon. Its pretty widely accepted I think.
http://www.rollitup.org/hydroponics-aeroponics/4387-lucas-formula.html

But last two days I've been flushing with tap water only to find the next day the pH is way down again. I just figured if they made a 7.5 liquid acidic then something was really wrong. The first time I only added enough tap water to bring the pH to about 5.8-6.0 but the next day it was way low again. Should I really go adjust the pH down to 6 now if I know it will be a 4 tomorrow?

I'm using a liquid indicator for pH

Could it be bacteria? My roots look healthy yes?

 

[bendoslendo]

Pic from just now, 2 days into flower cycle. New growth seems somewhat unaffected.

 

[lysol]

If it were bacteria physan 20 would murk it, technically u dont need a meter it just helps you keep things more stable, until you figure the problem out yeah I would slowly work your way up on those PH values to make sure its getting its' full range. Although I think this is more from the sudden changes which shock the plant rather then just a PH lockout, if you get a lockout soon make sure u treat it as the real PH problem that it is. I cant really tell from the pics if u have tip burn or not your leaves are a lil dark

 

[Ms_Weekend]

I dotn see any flowers yet why so much bloom? that is about what I use in FULL bloom(week5-8 of12/12)..... I would half your nutes and keep the water @ 5.5-6.3 to give alittle more leeway......meters are pretty necc. when doing hydro, soil can get away with more........but I think its those huge ph swings thats killing you & locking out nutes......If you have any final flush laying around try that for a few hours then go back to half nutes

 

[Ms_Weekend]

just saw your 2 days into bloom....go back to veg nutes & veg lighting or your buds are going to be compromised greatly.....got to get them healthy(er)....should use veg nutes 1-2weeks into 12/12 as they arent producing any buds yet.

 

[bendoslendo]

They aren't getting any nutes right now. They haven't gotten nutes in the last two days. They've been on tap water.

How do I raise my pH? When I add pH up it goes right back down super low then next day. It seems like I would have to add pH up every few hours to control the swings.

Does anybody have any idea what could be lowering my pH so much? I smell no foul odor and the roots look pretty healthy.

 

[lysol]

Nutes lower ph, try lowering your feed strength. is the PH dropping with just tap water? You should not require more then 24hrs flush.

if you keep your nutes within a range, your pH will stay within a range

Recommended reading: https://www.cannabis-world.org/cw/showpost.php?p=4394&postcount=13 ( goto thread view upper right for context )

 

[EvilTwin]

Bendo,
If you're using tap water without knowing what the EC is of that water...everything else is just guesswork. If your nute solution is cloudy, that usually means that something is precipitating out...meaning it's no longer available for the plant to use. Bite the bullet and buy a TDC/EC meter. Even if it's a cheap one.

What is the ph of your water from the tap? Are you allowing it to sit for 24 hours before using?
ET

 

[bendoslendo]

My tap water is about 8 untreated.It sits in a 50 gallon bucket before using, usually at least 24 hours.

So all last light cycle I monitored the pH of the DWC buckets. It went from about 7.5 to 7.0. It was just tap water, no nutes. I checked just now (about two hours ino this light cycle) and the pH is at about 4 again! So in one dark cycle it dropped from 7 to 4!

I read this http://www.gardenscure.com/420/hydroponics/88232-recirculationg-dwc-low-ph.html

The guy eventually decided it was lack of Dissolved Oxygen from clogged airstones when the roots got huge at the end of flowering. I think this is what happened to me at the end of last grow. I noticed the buckets werent bubbling as vigorously as they could be.

So last night I increased the airflow to both DWC by cutting off the flow to my bubble cloner. Bubbles now surge in both buckets. This didn't seem to help! If it were an issue of DO, would it take longer than one dark cycle before increasing airflow would help?

So should I dump buckets and refill with pH 6.0 or should I add pH up to the buckets gradually? I've never had this problem in veg before. I've never used Lucas formula, I've always used a dilute form (mr itos) of the GH 3 part. But I dont think its the formula because its happening even with plain water!

Why is it happening with plain water?

I wish there was an emoticon for jumping off a bridge

 

[guineapig]

Bubbling your water should raise the pH.....

man i feel your pain here- i've never seen anything like what is happening to you, but there must be a logical explanation for it......i am obsessed with pH so hopefully i can help you.....

Did the expanded clay get rinsed off? Could it have been holding acidic water which lowered the pH? How could the pH go from 7 to 4 so quickly with no explanation is what i don't understand....

kind regards from guineapig

 

[bendoslendo]

Right, the addition of CO2 to H20 should lower pH by creating carboxylic acid right? I think his reasoning was the oxygenation was required to prevent stagnant solution and mildly rotting roots. My roots seem healthy though, so I don't know.

The clay pellets were soaked in a mild bleach solution, then rinsed several times with tap water.

I used cpvc cement to put together the plumbing for the drain. Could this be the issue?

Should I use a H2O2? There is still remnants of mosquito dunks (BTi), so I guess that would end up killing the BTi. I don't think its the BTi causing the problem beause the issue is not occuring in my 50gal water rez. Also, the problem started occurring before the mosquito dunks, both the low pH and spotting. In fact I thought i had fungus gnat larvae that was causing the problem... i wish

 

[lysol]

Change your air stones every 3-6 weeks if you can, they tend to get clogged with rez solids for me, even soaking them in bleach and physan 20 doesnt unclog, theyre garbage after a few weeks nothing i try can clear them back out

 

[bendoslendo]

I'm going to swap out the oxy stones i have in there now with two brand new ones I have laving around. I dont know how great i cleaned those between grows. Thanks for the idea guinea and lysol.
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I found a brown slime on the clear line going into the oxystone. It doesnt have any scent. I don't know if it's just BTi colonization or if its some other bacteria causing my problem. It might even just be a percipitate of nutes or ph up.

In any event I switched out the line, stones, and added H2O2 to the rez.

 

[EvilTwin]

Hi Bendo,
Just a few thoughts before I go have breakfast...

If your water is ph 8, my guess is that it's running a TDS of over 300ppm. My tap water is ph 8 and is 330 ppm. It's mostly calcium that raises the ph.

Step two of my thinking. Your nutrient solution is cloudy. So that usually means you are precipitating out some of your nutes. The most common nutrient that precipitates out is calcium.

Conclusion. For some reason, and possibly the way you are adding your nutrients...you're precipitating out most of the calcium which lowers your ph and causes nutrient deficiencies.

Solution: Use better water. Even if you just buy enough water to mix 50/50 with your tap water...that would put you in a reasonable range.

The other issue is how you mix your nutrients. I'm very much hoping someone else will chime in here because this is a new issue for me. But always mix your nutrients in a bucket and dissolve thoroughly before adding them. Let them sit for awhile before phing and then add them to the res.
Peace,
ET

 

[bendoslendo]

So when I came home last night the pH was 7.0! Never thought I'd be so psyched to see a neutral hydro solution! Ha!


I dumped the tap/H202 solution and refilled with 1/2 strength veg nutes pH'd to about 6. When I checked the pH at the end of the light cycle, bam! Still 6.0!!!



My roots look a lot whiter now. I just hope my pH remains stable. I guess it was some kind of bacterial thing. I'm guessing the high acidity caused by the bacteria actually prevented the bacteria from being so overwhelming as to make a visible slime and stink.

Thankyou to everyone here for the helpful suggestions. Since I started growing again I've been looking all over the internet for a place that was like overgrow. This is definitely as close as I've found. My new home

 

[dyno]

Good to hear you got your ph issue sorted.

 

[mrred]

i would get a 3 stage RO filter off ebay for like 100, or go buy water with 5 gallon jugs from a stores RO filter, tap water has god only knows what chemiicals in it, you know they add fluoride too? just think, everything expect what your water supply adds is all pollutants. kinda crazy they add fluoride to protect our teeth, we an't suppose to drink it, it should be a crime to add fluoride to a public water system, it lowers iqs,it has a effect like mercury or lead, and in horses it gets in between their bones i belive and makes them lame.