pH up & down concentrate dilution method or ratio ?

cannaculturalist

cannaculturalist

Well-Known Member
Hi guys,

So I have a bottle each of Nutrifield's pH Up and pH Down concentrates and have found them to be super strong. I was thinking it would be easier to make a diluted solution for using - I'd hate to accidentally over do it directly in the reservoir. The bottle/company site doesn't give any details on how to do this, and my searching on RIU hasn't pulled up much info. What do you suggest is the best ratio to dilute this stuff to? (So far I've found a tiny dap will change 1L of water ~3 pH "units" eg pH 7 to pH 4 with the pH Down)

Details:
pH Up is 48% potassium hydroxide
pH Down is 81% phosphoric acid

Thanx
 
cannaculturalist

cannaculturalist

Well-Known Member
Hi jondamon,
Cheers for the response. That sounds like a pretty good plan. Would you recommend making this mix up each time, or would it be safe to keep for a while? - given all the delicacies of hygiene with hydroponics, I'm not sure if this would be best practice (obviously keep it in a light proof bottle away from heat etc if one would). Thanx
 
SaucyAussie

SaucyAussie

Active Member
This depends on a lot, not the least of which it total alkalinity. Total alkalinity is defined as a solution's (in this case, water or water with nutes) ability to resist a change in it's pH. This is affected by the total dissolved solids in the water (or nute solution). The higher the TDS, the higher the total alkalinity. Therefore, water with nutes in it or tap water with minerals in it will resist a change in it's pH far more than distilled water alone. I use distilled water exclusively, which is pH neutral (7.0), but since there are virtually NO dissolved solids in it the total alkalinity is very low, so it's prone to "pH bounce", meaning that adding even a small amount of an acid or base can cause a huge swing in pH. I use concentrated nitric acid to lower pH but whereas it only takes ONE DROP to lower a gallon of distilled water to pH 6.0, it takes four or five drops to lower a 500 ppm nute solution to 6.0. This is why you should ALWAYS adjust pH after adding nutes to your water.

Hope this helps,
Aussie
 
cannaculturalist

cannaculturalist

Well-Known Member
Hi SaucyAussie,

Cheers for the info! I'm using tap water, but it's very clean - 0ppm and average pH of 7.0-7.8. So far I've only needed to make up ~1L mixes of nutrients for seedlings, so am yet to see how much I'll be needing/use when I get onto an 80L system. With the few mixes I've made so far, I've pH checked the tap water and TDS to get a baseline, added nutrients, then checked pH and TDS again. An example would be 1L of 0ppm 7.8pH water + nutrients would be about 1 TDS (500ppm @ .5) and bring the pH down to around 6.4. Then I've added maybe 1 drop (hard to be precise in how much this is, but a tiny amount to be sure) of pH down to get close to pH 5.8. I'd imagine when doing a larger solution mix (80L) with similar starting water and nutrient ratio it'll be easier to manage - but a diluted pH Up/Down would allow for a bit more control of going overboard.

Interesting what you say about your water and how pH swings - even though mine isn't distilled, it seems to behave in a similar manner. And here's so celebrating the return of The Ashes (if that's you sort of thing).
 
1

1st Bud

Member
cannaculturalist said:
Hi SaucyAussie,

Cheers for the info! I'm using tap water, but it's very clean - 0ppm and average pH of 7.0-7.8. So far I've only needed to make up ~1L mixes of nutrients for seedlings, so am yet to see how much I'll be needing/use when I get onto an 80L system. With the few mixes I've made so far, I've pH checked the tap water and TDS to get a baseline, added nutrients, then checked pH and TDS again. An example would be 1L of 0ppm 7.8pH water + nutrients would be about 1 TDS (500ppm @ .5) and bring the pH down to around 6.4. Then I've added maybe 1 drop (hard to be precise in how much this is, but a tiny amount to be sure) of pH down to get close to pH 5.8. I'd imagine when doing a larger solution mix (80L) with similar starting water and nutrient ratio it'll be easier to manage - but a diluted pH Up/Down would allow for a bit more control of going overboard.

Interesting what you say about your water and how pH swings - even though mine isn't distilled, it seems to behave in a similar manner. And here's so celebrating the return of The Ashes (if that's you sort of thing).
Click to expand...
I saw you having Tap water with 0 ppm, is that even possible?
 
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