Adjusting pH in DWC solution

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FLLW

FLLW

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This seems to have become more problematic lately, the issue is dialing in a pH.
I use 2.5 gallons of RO water and .5 gallons well-water per DWC tank.
For topping-off during the week I use either the RO/well-water combo or straight well-water.

As a rule I mix my solution the day before I do the actual solution change.
When I'm done mixing my chemicals I'll adjust the pH down to around 6.0.
I then place an air-stone in the solution and let it aerate over night.
Invariably the solution's pH will rise overnight.

Prior to doing the solution change I again take the solution down to around 6.0.
This has generally worked well on solution changes but not so well when trying get the pH down on my between-changes top-off water.
Yesterday I had to keep adding pH Down (acid) to my top-off water until it stunk like a Yellowstone geyser and I could not get it to 5.5 (eventually I tossed this water because of the stink - I wasnt putting something like that in my plants).

I even called up General Hydro's help line and the guy on there said," pH is tricky. Just keep adjusting."

Anyone got a hack to solve this problem?
B01C00D1 4134 45B3 BBFD 3CE40F8F3429 1 105 c
B01C00D1 4134 45B3 BBFD 3CE40F8F3429 1 105 c
 
Habosabin

Habosabin

890
143
I use a ph stabilizer when I use RO. This might help.

your plants look great. Btw
 
3730E773 DAC6 4D95 8FFC DDE6892F9C1A
FLLW

FLLW

16
3
your plants look great. Btw
Thanks, that was a couple weeks ago.

Regarding the pH stablizer: that's why I include half a gallon of well water when mixing solutions.
Let me explain: pH/Osmosis Stabilizer web page says,"Due to its very low ppm, RO water is prone to dramatic fluctuations when nutrients are added, or even just from exposure to air . . . pH Stabilizer provides the perfect blend of minerals to RO water so it stabilizes pH while not causing any unwanted chemistry."

I'm willing to give it a try for $10 or so.
Have you found it works for you?
I should point out I've had more trouble setting the pH in pure well water (around 270 PPM) for topping-off than I have with my actual DWC solutions that are
5-:1 (RO to well water)
6DFB6C23 A252 4DFA A787 5D46BDABA64C 1 105 c
6DFB6C23 A252 4DFA A787 5D46BDABA64C 1 105 c

These are the girls today finishing their 3rd week of flower.
The drill is there for scale.
The tube hanging down (in the foreground) is 18" from my lights this helps me keep the gap between light and plants at the right height
 
Last edited:
Habosabin

Habosabin

890
143
I should just use my tap water that is 500ppm. I was thinking of using that as a substitute for the stabilizer. The stabilizer seems to work for me but I wish it was $10. I think it's more like $20 to $25. I check my ph daily and if I set it to 5.8 it can get to 6.2 by the next day. I haven't see it over 6.2 yet.

Your plants look really healty and lush.
 
FLLW

FLLW

16
3
Its been a good grow but just lately I can't adjust pH properly.

I'm ordering the stabilizer from Amazon, with free shipping it was my cheapest option around $32.

I appreciate the tip on the stabilizer.

I've got another call into General Hydro, if I hear anything worthwhile I'll post it in this thread.
 
Cashmeh

Cashmeh

1,781
263
Bro, you will never be able to have a stable ph in dwc with low water capacity. Dwc is meant for entry level hydro growers, mainly grow just one. Once you complete one successful DWC, switch to RDWC. You can do it now if you want. I would buy these strips first. . understanding whats in your water goes along ways.


So if you want stability you need alkalinity and high holding capacity. I use 60 gallons of water for 6 plants. My Ph stays stable until late flower. I also have P and K testing strips/tritates.

For now, fill your res to the netpot, keep as much water in there as possible. Add around 70 ppm of ph up when your all done, then ph down to 5.6 or whatever your use to.

Rdwc is where you need to be, far more stable. You couldnt pay me to run a dwc bucket, let alone 4.
 
FLLW

FLLW

16
3
Bro, you will never be able to have a stable ph in dwc with low water capacity. Dwc is meant for entry level hydro growers, mainly grow just one. Once you complete one successful DWC, switch to RDWC. You can do it now if you want. I would buy these strips first. . understanding whats in your water goes along ways.


So if you want stability you need alkalinity and high holding capacity. I use 60 gallons of water for 6 plants. My Ph stays stable until late flower. I also have P and K testing strips/tritates.

For now, fill your res to the netpot, keep as much water in there as possible. Add around 70 ppm of ph up when your all done, then ph down to 5.6 or whatever your use to.

Rdwc is where you need to be, far more stable. You couldnt pay me to run a dwc bucket, let alone 4.
I use pH meter not strips.
Turns out the problem was the pH meter.

BTW this is my 5th (or more) grow using DWC. I generally get about a pound per grow in an 8'x7' grow room.
Don't you have to keep your buckets in a fixed position with RDWC?
If so I won't I going to RDWC anytime soon.
My plants are on on coasters and I can spin them to do LST and to get light to all areas of the plant.
 
FLLW

FLLW

16
3
I figured out the problem with some help from Hanna Tech Support.
I did a calibration while I had the Hanna on the phone and it could be determined that the probe of the pH meter was shot.
It was a high stress situation for 2 reasons:
1. I couldn't prep topping-off water because of the bogus meter so my plants were about 1 gal from empty (they're going through about a gallon a day currently).
2. Yesterday was my solution change day and I had no idea of what the pH was in my prepped solutions (so I couldn't/shouldn't add it).

Knowing the meter was shot was a step in the right direction.
However I live deep in the country.
120 miles later I was able to get home with a Bluelabs meter.
Turns out my freshly prepared solution had a pH in the 2's (good thing I didn't put in the tanks).

What did I learn from this?
Hydro-growers need a back-up pH meter.
Fortunately I've got two Hanna's that only need the probe replaced (total about $100).

I wont start another grow without a backup meter and I guess I'm lucky this grow got this far with out a single burnt leaf tip.

If you offered a suggestion, Thank you!
It's appreciated.
 
Cashmeh

Cashmeh

1,781
263
I use pH meter not strips.
Turns out the problem was the pH meter.

BTW this is my 5th (or more) grow using DWC. I generally get about a pound per grow in an 8'x7' grow room.
Don't you have to keep your buckets in a fixed position with RDWC?
If so I won't I going to RDWC anytime soon.
My plants are on on coasters and I can spin them to do LST and to get light to all areas of the plant.
Yea I started with a junk ph meter like you and had all the same issues. I then got a decent ph meter that can be calibrated using calibration solution. My ppm meter also can be calibrated with my solution. So every few days I make sure they are accurate. The strips do mention ph, but they also give you nitrate and nitrite info, hardness, and most importantly, alkalinity which is what most lack. I can test the ppm levels of npk individually. Anyways no biggie..

I have a hydro transplant system where I must cut roots apart because they are tangled with other vegged plants. I then put in my flower room. Two month veg, two month flower. Two pounds in a 4x8 using two 1000w hid every two months. I adjust ph once a week and now that I have more testing equipment I do not plan on doing a full res change, only top offs.

As for spinning plants, never heard of someone doing that but I mean you can spin them in the netpot I guess. If you just do larger totes you will be fine. The 3-5 gallon capacity during late flower is what got me. Had to be in there adding shit every day, sometimes twice a day.

Some people like to mess with the plants, I just have other things to do. I can go on vacation for 4 days during late flower. Ph started at 5.6 and rose to 5.8 over 4 days.. Easy peasy

So my veg tent has a 30 gallon tote in it with holes drilled in the top for netpots. you can do one instead of 4.

So the reason why people need to switch from Dwc to rdwc is because of water column nutrient and 02 consistency. those air bubbles do not mix water and do not provide 02 to the bottom of the bucket. without a pump recirculating nutrients your roots willbecome long and stringy as they have to search for food.

I guess if you don't mind messing with them, at least figure out how to implement a water pump. I can assure you that it will increase your growth rates... But to each their own.
 
AeroponicApparatus

AeroponicApparatus

22
3
Glad you got it somewhat figured out! I run a very small DWC, and throughout my first grow had countless issues with PH. I bought the Blue Lab PH Controllet, & an Iceprobe, now I can live life outside of the grow room. I'll eventually switch to RDWC when I have more room, now that I've figured out all of my variables.

I use 100% distilled water.
1.5 gallons in a 2 gallon res. I don't like the dirt that holds the seed in place to constantly be wet. I noticed bacterial growth on my last grow and had to start over.
CES noots & ph down. With hydrogaurd.
 

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