PH Adjuster dilution prior to adding to Reservoir

Indoor Growing Hydroponics
#1

So I’ve heard that adding undiluted ph up or down to a reservoir precipitates calcium magnesium and Phosphate rendering them unavailable. Which may cause issues with deficiency in plants… Which I’ve experienced and couldn’t figure out why… And so I’d just add more… I’d also find gunk at the bottom of my Reservoir I couldn’t explain…

Source: https://youtu.be/X5vLME0N-54
4min 23sec in

So my question is, how much do I dilute my ph adjusting solutions? 25-50%? How much is enough to negate this effect? Also is it due to the acids composition or is it just due to the difference in ph between the reservoir and ph adjustment liquid added?

Seems to be a differential… So my more specific question would be then, what ph do I need my adjuster to be before adding it to the Reservoir? How much of a differential is good or bad when mixing liquids?

Ph down is around what, 3~4? So then mixing solutions with around 2-3ph differential causes precipitation?? That doesn’t sound right, if it was this narrow I’m sure more people would have mentioned it… Hopefully someone knows specifics.

Also why does Nobody making these adjusters bring this up? Not general hydroponics, or any other company? I’ve never heard any grower bring it up and most successful growers actually say “I’ve never heard of it and am fine so I won’t be changing my ways now”…

Thanks

J

1 Like
#2

I’ve seen it happen before, depending on what you’re adding and source water.

I used to get cloudy precipitate in very hard water especially using silica supplements and higher strength nutrients.

I’m sure if you dilute it 1:10 you’ll not see any issues. Then again, I’ve grown in such hard water that the nute reservoir develops a calcium crust after just a few weeks. Adding 10-20mL is as inconsequential as adding 1-2mL but then again I mix 5-10 gallons at a time everyday.

pH down is probably closer to pH 2.5-ish. Pure phosphoric acid is about 1.5.

If you’re seeing precipitate from hard water can you cut it 50% with the runoff from the AC and/or dehumidifier?

It’s hard to know, but I had less issues adding the pH down first, mixing, then nutrients with super hard water. Once you get the formula right it’s easy.

Cal, Mag, and Phos and other alkaline metals are more available at higher pH which is why I shoot for 6.3-ish. I feel the standard pH charts should better reflect that because standard consensus for all hydro seems to be 5.5-5.8. Which is really more for pure water culture and even that’s a bit low. I had issues under 6.0

3 Likes
#3

Thanks for the info.

Yea I use RO. I started using a meter which uses 0.1mL doses automatically and it’s such a small amount I don’t have issues vs 0.25 or 0.5mL a few times a day (when needed)

I think my bigger issue now is the order of adding ingredients. I wrote a new post about it. Maybe you can chime in.

It’s about ingredients based on ph vs type.

Thanks