Ph'ing water in DWC system question?

[Smee23]

I think I may be having problems with PH'in my DWC system.

I PH my water to 5.5 - 5.8 and allow my system to settle a bit (pumps on etc)

I then re-check and the PH always go up to about 6.5 on average.

I'm confused at what the real PH is and if it's reading this high shall I gradually lower it over the week before I do a complete tank change or shall I PH my water to about 4.8 and let it rise to my desired PH level. Or just PH at 5.5 -5.8 and accept this is the real PH?

Cheers guys for your help and advice

 

[BobCajun]

Just bubbling water through nute solution raises its pH. What I've read says that it does it by driving off CO2 from the water, but seems a little fishy to me. How much CO2 could be in there? But however it does it, it raises pH.

 

[Smee23]

I'm using a 42 litre container with two 5 inch air stones and only growing a single plant in the stealth unit I built. I've just been struggling to understand what the scientific true PH is, whether it's when I've just completed a reservoir change or like 12 hours after. I understand that there's going to be a chemical reaction which might change PH slightly but by 0.5 - 1 is just hard for me to get my head around. Is there any way I can stop this or do I just PH down to 5.5 12 hours after reservoir change ?

 

[BobCajun]

I'm using a 42 litre container with two 5 inch air stones and only growing a single plant in the stealth unit I built. I've just been struggling to understand what the scientific true PH is, whether it's when I've just completed a reservoir change or like 12 hours after. I understand that there's going to be a chemical reaction which might change PH slightly but by 0.5 - 1 is just hard for me to get my head around. Is there any way I can stop this or do I just PH down to 5.5 12 hours after reservoir change ?

Could try using malic acid as a pH buffer. Here's the details, just use potassium hydroxide/carbonate (commercial pH up) instead of sodium hydroxide, producing potassium maleate instead of sodium maleate. You wouldn't have to purify it as much as in the text, with crystallization. In another article they just made a solution of 23 g malic acid to a liter of water and added sodium hydroxide until it was at the pH they wanted. That stock solution could then be diluted as desired. So just the same thing but using potassium hydroxide instead.

source

 

[BobCajun]

Actually I just did a quick search and potassium malate or maleate can be bought as a food additive, so you might not even have to make it yourself. I don't know what the pH is of potassium malate compared to sodium. From what I could find looks like it might be 7. Here are some amino acids that can be used as buffers. Just find the pH you want. Triglycine might be good, or maybe isoglutamine. I haven't researched this any further.

 

[Airwalker16]

Just add your pH ups and downs as needed man.

 

[Craig1969SS]

Tap water will migrate back up after lowering. RO should be stable for a day or two at least.

 

[Airwalker16]

Tap water will migrate back up after lowering. RO should be stable for a day or two at least.

My ro stays stable for weeks using just GH flora trio series. Don't even add ph adjusters EVER. It's brings the 7-8 ph ro down to a perfect 5.8-6.5 every time.

 

[Cx2H]

Greetings turn the bubbles down a little bit. A lot of bubbles will raise PH. Micro activity will raise PH. Powder nutes with sheetty buffer will raise PH. Water should set up 45 mins first anyway and re-adjusted. I use tap with 0 issue in DWC.. RO water is a pain in the arse to source and amend.

 

[Airwalker16]

Greetings turn the bubbles down a little bit. A lot of bubbles will raise PH. Micro activity will raise PH. Powder nutes with sheetty buffer will raise PH. Water should set up 45 mins first anyway and re-adjusted. I use tap with 0 issue in DWC.. RO water is a pain in the arse to source and amend.

Its fucking cake bro. You buy a sink ro kit for $150. Then get a black 50 gal, low profile, tote with a nice sturdy square body near the sink and up off the ground a good 15" and install a spigot on the corner of it. Turn on your ro with a black vinyl tube running from it to a hole in the totes lid and just forget it. It fills up in like 2 days and you just open the spigot and fill your 5 gal jugs.

 

[Cx2H]

Yeah that's crafty.

 

[Airwalker16]

Yeah that's crafty.

And EXACTLY what I do.

 

[Michiganjesse]

Got one under my sink with well water it's nice to drink and water my plants with

 

[Dumme]

Carbonates work the same in any system.
A video explaining, for you pleasure...

 

[BobCajun]

If malic acid is used for pH down it also acts as a chelater to make minerals more available. BTW, I read that if vinegar is used as pH down it can cause slime to grow in the res, because there is sometimes "mother of vinegar" bacteria in it which will then grow in the res.

Oddly enough, I couldn't find one thing about using malic acid as hydro pH down. I don't think anyone ever tried it. Guess they just went straight to acetic acid because it's so common and the most obvious thing you could think of. You can buy malic acid in brewing stores. Haven't tried it yet myself. BTW, I previously thought malic acid and maleic acid were just different spellings of the same compound, but I found out that it's actually a separate compound.

 

[Getgrowingson]

Invest in a blue lab doser. I constantly chased ph In dwc and had the ups and downs. When it goes up what is your ppm doing? I've always found as ppm goes down ph goes up and vice versa. Once I invested in a dosing unit my yield plant health and ease of caring for the plant all went much better. Dwc can be a bitch but a sweet bitch who puts out like no other. Trust me bro if your serious about dwc get a dosing unit.

 

[Airwalker16]

Invest in a blue lab doser. I constantly chased ph In dwc and had the ups and downs. When it goes up what is your ppm doing? I've always found as ppm goes down ph goes up and vice versa. Once I invested in a dosing unit my yield plant health and ease of caring for the plant all went much better. Dwc can be a bitch but a sweet bitch who puts out like no other. Trust me bro if your serious about dwc get a dosing unit.

Never used one of those before. But I at least can tell you, with GH 3 part series nutes and r/o water, your pH won't give you ANY PROBLEMS at all. Shit stays perfect, right from the time you're done mixing. No adjusting required.

 

[Craig1969SS]

Never used one of those before. But I at least can tell you, with GH 3 part series nutes and r/o water, your pH won't give you ANY PROBLEMS at all. Shit stays perfect, right from the time you're done mixing. No adjusting required.

If your pH stays stable "for weeks " in dwc, 5.8" -6.5 it only varies by .7 the whole time...Are you not growing anything in the solution? Or are u saying your stock tank..which isn't feeding plants stays stable? Big difference that needs to be clarified please.

 

[Airwalker16]

If your pH stays stable "for weeks " in dwc, 5.8" -6.5 it only varies by .7 the whole time...Are you not growing anything in the solution? Or are u saying your stock tank..which isn't feeding plants stays stable? Big difference that needs to be clarified please.

It's RDWC, 25-30 ish gallons, constantly being mixed throughout the buckets.

 

[BobCajun]

GH have pH stabilizers in their products, at least some of them. They only say that you may need to adjust the pH due to water quality and pH varying by region and season. If you use RO water, you shouldn't have to adjust at all, though it does say high growth rates may destabilize it. But it has pH buffers, like I was describing earlier. They don't say what the buffer is but it's the same idea.

"To maximize plant growth, the pH level of your nutrients should be slightly acidic. Experienced growers consider the ideal pH for most crops to fall between 5.5 and 6.5. Users of General Hydroponics nutrient products generally do not experience problems maintaining the proper pH range because our formulas are pH buffered. However, some important exceptions do exist. pH can acidify to an unacceptable level when nutrient solutions are used with poor quality water, or pH unstable media, such as rockwool. High growth rates can also destabilize pH." http://generalhydroponics.com/ph-buffers/