Automatic ph doser?

OldMedUser

Well-Known Member
I've known a couple people that have used them and they went through liters of pH up and own in no time and if fucked everything right up.

My DWCs would go up to about 6.3 between 3 day top ups and I'd top up with RO, Check pH and ppm then use conc. sulphuric acid to drop the pH to around 5.4. I turned into an auto pHer as after a few top ups I'd just add 4 or 5 drops of acid if I didn't feel like testing as it was so regular.

Then I got pH Perfect nutes and forgot about pH altogether, :)

:peace:
 

vostok

Well-Known Member
I've known a couple people that have used them and they went through liters of pH up and own in no time and if fucked everything right up.

My DWCs would go up to about 6.3 between 3 day top ups and I'd top up with RO, Check pH and ppm then use conc. sulphuric acid to drop the pH to around 5.4. I turned into an auto pHer as after a few top ups I'd just add 4 or 5 drops of acid if I didn't feel like testing as it was so regular.

Then I got pH Perfect nutes and forgot about pH altogether, :)

:peace:
me too and shifted to the soil-organics 'hood' never again ..lol
 

JSB99

Well-Known Member
I've known a couple people that have used them and they went through liters of pH up and own in no time and if fucked everything right up.

My DWCs would go up to about 6.3 between 3 day top ups and I'd top up with RO, Check pH and ppm then use conc. sulphuric acid to drop the pH to around 5.4. I turned into an auto pHer as after a few top ups I'd just add 4 or 5 drops of acid if I didn't feel like testing as it was so regular.

Then I got pH Perfect nutes and forgot about pH altogether, :)

:peace:
Once I get mine balance, it's locked in. It doesn't sway at all. If I add a teaspoon of Maxi, I either add 5-gallons fresh water or 5mil pH up. This is by far the most stable system I've had, but I think part of it has been due to the GH Maxi nutes I'm using. I had some shifting with the Floro Trio, but not with the Maxi. I mentioned before that the Maxi series are the only nutes that drop my pH.
 

Xs121

Well-Known Member
The swinging of ph in tap water is due to free ions and carbonate in water, mixing them directly to your reservoir and aerating it just speeds up the outgassing process which would result in wide ph swing.

What I do is mix my nute in tap water and let it sit for 24 hrs at least (or tap water only, open cap) without ph up/down and when I'm ready to use it, I aerate it for a few hrs then ph it to the desired level. The most ph swing I've seen is .1pt in 24 hrs.

Tap water coming out has a temporary hardness value and this is chemically unstable. The trick is to let the water outgass until it reach permanent hardness. This is the point where the true ph of the water is stable.

p.s. I edited the 1pt to .1pt after rereading it (ex; 5.8+ swing up to 5.9+), my bad
 
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The swinging of ph in tap water is due to free ions and carbonate in water, mixing them directly to your reservoir and aerating it just speeds up the outgassing process which would result in wide ph swing.

What I do is mix my nute in tap water and let it sit for 24 hrs at least (or tap water only, open cap) without ph up/down and when I'm ready to use it, I aerate it for a few hrs then ph it to the desired level. The most ph swing I've seen is .1pt in 24 hrs.

Tap water coming out has a temporary hardness value and this is chemically unstable. The trick is to let the water outgass until it reach permanent hardness. This is the point where the true ph of the water is stable.

p.s. I edited the 1pt to .1pt after rereading it (ex; 5.8+ swing up to 5.9+), my bad
Thanks for the info do you aerate the water when you let it sit or just let it sit?
 

OldMedUser

Well-Known Member
The swinging of ph in tap water is due to free ions and carbonate in water, mixing them directly to your reservoir and aerating it just speeds up the outgassing process which would result in wide ph swing.

What I do is mix my nute in tap water and let it sit for 24 hrs at least (or tap water only, open cap) without ph up/down and when I'm ready to use it, I aerate it for a few hrs then ph it to the desired level. The most ph swing I've seen is .1pt in 24 hrs.

Tap water coming out has a temporary hardness value and this is chemically unstable. The trick is to let the water outgass until it reach permanent hardness. This is the point where the true ph of the water is stable.

p.s. I edited the 1pt to .1pt after rereading it (ex; 5.8+ swing up to 5.9+), my bad
Totally correct about the tap water. I've explained to a lot of new growers how that works. I use nothing but RO water and it almost always is less than 10ppm if not lower from the place I buy mine. I still had the pH go up to 6.2 or 6.3 after 3 days but it wouldn't go higher than that so I guess that's were the older AN nutes would want to be. Can't seem to get a real reading from the pH Perfect nutes so after getting them I just don't bother testing and plants grow fine in DWC or soil/soilless.

I tell guys to run a little experiment. Get a liter or some other amount you know how much it is and check the pH and write it down. Then add enough pH down to get to the level you want and preferably run an airstone in it or at least mix it up a few times for the next 12 - 24 hours then check the pH again. If it's back up to the same as fresh out the tap then you've got hard water with lots of carbonates in it and they are very slow to react with the acid in the pH down. Keep doing the pH down keeping track of how much of that you use the whole time too.

Once you get it to the point where the pH will stay at teh level you want and not wander up any more then you will know how much pH down you need to get your water stable and can just add that amount to a batch of water and know it's the right amount to use. Keep an eye on the ppm of your tap water as that will change with the seasons in many places that use surface water as a source so the amount of pH down will have to be adjusted to suit.

:peace:
 

Xs121

Well-Known Member
Thanks for the info do you aerate the water when you let it sit or just let it sit?
If you can aerate your water or nute mix for a while (12-24 hrs) the better, before using it. Note too, that when you aerate your reservoir, you're not only adding oxygen but you're also adding CO2 to your reservoir. And CO2 (combine with temperature) can react with existing minerals and change the acidity or alkalinity of your reservoir. So by aerating it ahead of time, you get a more stable composition of your water/nute mix.
 

Xs121

Well-Known Member
Totally correct about the tap water. I've explained to a lot of new growers how that works. I use nothing but RO water and it almost always is less than 10ppm if not lower from the place I buy mine. I still had the pH go up to 6.2 or 6.3 after 3 days but it wouldn't go higher than that so I guess that's were the older AN nutes would want to be. Can't seem to get a real reading from the pH Perfect nutes so after getting them I just don't bother testing and plants grow fine in DWC or soil/soilless.

I tell guys to run a little experiment. Get a liter or some other amount you know how much it is and check the pH and write it down. Then add enough pH down to get to the level you want and preferably run an airstone in it or at least mix it up a few times for the next 12 - 24 hours then check the pH again. If it's back up to the same as fresh out the tap then you've got hard water with lots of carbonates in it and they are very slow to react with the acid in the pH down. Keep doing the pH down keeping track of how much of that you use the whole time too.

Once you get it to the point where the pH will stay at teh level you want and not wander up any more then you will know how much pH down you need to get your water stable and can just add that amount to a batch of water and know it's the right amount to use. Keep an eye on the ppm of your tap water as that will change with the seasons in many places that use surface water as a source so the amount of pH down will have to be adjusted to suit.

:peace:
RO water has a stable ph mainly because of the lack of dissolved minerals. I believe between 5 and 6. Perfect for hydro but not everybody want to spend on RO water.
 

OldMedUser

Well-Known Member
RO water has a stable ph mainly because of the lack of dissolved minerals. I believe between 5 and 6. Perfect for hydro but not everybody want to spend on RO water.
RO or distilled water has no pH of it's own so can't be properly measured with a pH pen as there should be zero H+ or OH- ions in the water to give it a pH. As it has no buffering capability at all just a few drops of pH down in a 5 gal jug will read in at 5 or so. A few drops of the same in tap water won't even budge the reading as that little bit of acid will be used up in no time.

I'd prefer not to be buying RO myself but our dugout water would totally mess up indoor grows whether in pots or hydro. Most of the problems I see growers in the forums have is water related especially later in flowering when the buildup of minerals from tap water make it impossible to keep below 7. So many nOObs think that if they pH their feed water down to 6 it will make the root zone 6 but that's not how it works.

If in hydro with tap water a complete change should be done once you have added back as much water as your system holds to prevent salts buildup from hard water. Weekly changes aren't needed when the plants are small to medium in size and I've done many DWC grows without ever changing the nutes. Just lowering the ppm by removing some nutes and topping up with RO near chopping time. I harvest the big colas first then give the plants another 10 days or so to ripen up the lower ones so like to keep about 300ppm in the tubs.

:peace:
 
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