best/safest regular PH Down?

[fourtwenty]

Does anyone have experience with the Hesi line of ph products?

 

[Grenouille]

If you run organic with the coco, then using vinegar or/and citric acid works very well, although they have less power to drop ph than stronger acids. But both, and specially citric works well in organic. (get pure lemon juice)

For standard acids, there are three commonly used acids:

-Nitric acid. A strong acid, it drops ph quicky just adding little quantities. You will want to use it during veg and early flowering. Too much N in late flowering stage often isnt a good idea, because it gives bad taste and require longer curing time. Excess N can disminish your harvest. But it depends of the nute profile you are using in flowering: it its very low in N, then you can use nitric acid as ph down for all the run.

-Phosphoric acid. Its a weak acid, but in contrast, its capable of give 3 H+ in following reactions, thus giving the higher ph stability of any acid used in hydro. As in late flowering, plants require large P quantities, its often used in this stage, while P requeriment in veg are quite low, thus isnt recomended in veg.

-Sulfuric acid. Very often forgotten, its probably the best Ph down. Its a very strong acid, wich require very little quantities to correct ph. S content can range from very low levels to very high ones without mayor problems related, although, similar to N, too much S can affect taste. Choosing a nute profile low in S (as Canna nutes) allow to use it along all the run.

thanks for the help everyone, this post in particular.