pH Before or After Adding Nutrients?

I have found that by adding my ph up/down first, I can reduce the amount required instead of adding it after I add nutes.

For example: I needed 0.049ml of ph down (phosphoric acid) if I added it before adding nutes. After adding nutes that would bring me to the magic 5.8 number. If I added nutes, then ph down, I needed like 0.069ml of ph down to get me to 5.8.

I'm now needing to ph up (potassium hydroxide) and find the same thing. If add ph up then nutes, I need less ph up than I would if I were to add nutes then ph up.

Not sure what's going here chemistry wise. I'm suspect that it could be the small amounts of lime in my water that's causing this - soft rainwater stored in concrete tank - 10-20ppm (0.5). pH varies depending on the time of year (7 in winter, as high as 11 in summer).

Is it okay to ph up/down first and then add nutes? It appears that I need the ph to be around 8 for veg nutes and 9 for flower nutes for the concentrates to bring it back to the 5.8-6.0 region. Is this going to cause any weird bonding or screw my nutrient solutions in any way?

Hope that makes sense... Cheers!

I would not ph before adding nutes. Sounds like bonding, or dropping out of solution to me.

Have you checked after a couple of hours to make sure it remained the same?

Should you see initial cloudiness when adding ph up to a neut solution that has been very well mixed?.

Dalek Supreme said:

I would not ph before adding nutes. Sounds like bonding, or dropping out of solution to me.

Have you checked after a couple of hours to make sure it remained the same?

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It sounds like it's doing that (or something) when I ph up/down after adding nutes. That's what has me baffled. If I mix my nutes and then ph up/down, I need more of it than I would if I were to ph up/down first. To me, that sounds like there's bonding (or something) going on if I adjust the ph after adding nutes... I'm by no means a chemistry expert though

And yeah the ph is stable afterwards. If I place the nute mix in an air tight dark container it remains stable for weeks. If I leave it out un-airated, it goes cloudy/funky after about 3-4 days but the ph remains stable.

Flowki said:

Should you see initial cloudiness when adding ph up to a neut solution that has been very well mixed?.

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No there does not appear to be any difference. Other than a nuted mix requiring more ph up than it would if I buffer the ph first.

Dude at the hydro store told me to ph before adding nutes, but I was doing it after so who knows?

pH before adding nutrients if your pH is going through the floor or roof. Then in that case do buffer against it shooting that high or low. One thing we do is add Silica first this helps with RO water if you don't want to add Cal Mag as a buffer. Or just add a Ca Mg product.

ThaMagnificent said:

Dude at the hydro store told me to ph before adding nutes, but I was doing it after so who knows?

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that guy who told you that is giving misinformation, hes trying to weaken his competition.

outlier said:

Is it okay to ph up/down first and then add nutes?

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That's how I do it. I add the amount of pH down (10% nitric acid) I know will be needed before adding the nutes, then I add the nutes.

Of course this only works if you already know how much pHDown/phUp you will need so that after adding your nutes you get ~5.8. I always add 40mL of 10% nitric to 4 gallons of hard tap water and it doesn't really matter if it goes in first or after as long as it's 40mL.

churchhaze said:

That's how I do it. I add the amount of pH down (10% nitric acid) I know will be needed before adding the nutes, then I add the nutes.

Of course this only works if you already know how much pHDown/phUp you will need so that after adding your nutes you get ~5.8. I always add 40mL of 10% nitric to 4 gallons of hard tap water and it doesn't really matter if it goes in first or after as long as it's 40mL.

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Awesome, thanks churchhaze!

I still find it odd that I need slightly more ph up/down if I adjust the ph afterwards. Whether that's due to my nutes, the lime from the concrete or something else... I have no idea

I believe you are supposed to dilute 1 part pH adjuster to 100 parts water before adding to a nutrient solution.

adding pH before nutes does this and there is no problem doing that if you are in a routine and know exactly how much pH down you need.