Mixing nutes in high-pH tap water

[rollyouron]

9 pH is fairly normal from city water. It prevents corrosion from the upstream pipes. If Flint, MI figured that out a bit earlier, they wouldn't be in the state that their in.
Out of my RO, I get a pH of 8.8 but there's nothing to buffer it at that level so it immediately drops to 4.9 after I add nutes.

Yes my Mom and Dads well water is 5.8 from tap. Their water will eat through copper pretty fast. Had to replace any appliance hook ups with plastic.

 

[2Ton]

Hi all,

If I have tap water with a high pH (~9), will it be an issue to mix nutrients without lowering the pH a little bit first? In general, does nute lockout occur quickly, or will adjusting pH after mixing prevent it?

From what I've gathered, most people recommend adjusting pH after adding nutes, but I haven't been able to find an answer when the starting water has a high pH.

Using one digital pH meter and liquid pH tester for comparison. pH around 9, and I have a TDS meter that reads 85 ppm (apologies, I don't know the actual EC or conversion rate).

First post, and happy to have finally joined RIU! Got a half dozen soil grows under my belt, this is my first attempt at hydro.

Always mix nutes then ph!!!

 

[The_Enthusiast]

I'm not sure if chelated nutrients get back to their chelated form after high PH.

I know that bond between EDTA or some other chelate breakes in high PH - I really don't know if it reverts after the PH is lowered like some other compounds.

I always lower PH before adding chelated nutrients.

And, just for your info - adding "PH minus" changes your "NPK ratio" (because it is usually phosphoric acid or nitric acid) so just be aware of that.

 

[chasingwaterfalls]

I'm not sure if chelated nutrients get back to their chelated form after high PH.

I know that bond between EDTA or some other chelate breakes in high PH - I really don't know if it reverts after the PH is lowered like some other compounds.

I always lower PH before adding chelated nutrients.

And, just for your info - adding "PH minus" changes your "NPK ratio" (because it is usually phosphoric acid or nitric acid) so just be aware of that.

Hm, thanks for pointing out that i should take the actual acid into consideration.. in your experience, is it something that i should adjust for?

I was in a 20gal tote, but moved back to a 5gal for now. I think I'll adjust pH first, as it seems like there's also no harm in adjusting first.

Thank you for the input, since it seems like there's more of an agreement to adjust pH after, but it makes sense that having a high pH is an exception

 

[The_Enthusiast]

Hm, thanks for pointing out that i should take the actual acid into consideration.. in your experience, is it something that i should adjust for?

I was in a 20gal tote, but moved back to a 5gal for now. I think I'll adjust pH first, as it seems like there's also no harm in adjusting first.

Thank you for the input, since it seems like there's more of an agreement to adjust pH after, but it makes sense that having a high pH is an exception

Manufactures of Liquid fertilizers say that add PH down (acids) after adding nutrients - because most nutrients as well lower PH.

But make a test batch, take 10L (3 gal or something) and first add nutrients than lower PH with acids (try to spread between Nitric, Phosphoric(you shouldn't have more than 100 ppm of P - it's not optimal), Sulfuric (doesn't change "NPK ratio" and plants absorb it as needed) acid if your PH is high).

When you get a good ratio than use it from that moment on but first add "PH down" before nutrients.

If you are using tap water - it has a tendency to change it's composition in different stages of year (summer vs winter) so take it in a consideration.