Not all PH down solutions are equal

[lightyear]

I’ve been down a long, frustrating road with PH adjustment solutions, and I just wanted to share my results in hopes it will help someone else avoid what I just went through.

I’m gonna just skip to the chase first, and I’ll explain below.
TLDR-
Dyna-gro is the only PH down I’ve found that truly holds a stable PH level for a week or more. I can set my reservoir and forget it for the week, aside from monitoring the water level.

Let me explain:
There’s a key difference with Dyna-grow’s recipe - nitric acid. The rest use phosphoric acid alone or in combination with citric acid. And ALL of those need PH adjusting in two days every single time. I’ve done side by side experiments just to be sure, and every time the Dyna-gro holds its PH level and the rest drift back to the tap water’s original level it was from the sink in 48-72 hours.

So, if you’ve been constantly adjusting PH to maintain a proper level, please give this some thought.

[RookieBuds]

N P K numbers on a pH adjustment product??? That never even dawned on me as being a thing.

Interesting info, thank you for sharing.

[lightyear]

Yep, it’s nitrogen derived

[the_bot]

They should, in the end phosphoric acid has… phosphorous. Nitric acid has nitrogen. Its better if they do so you know the proportion.

@lightyear thank you for the post. I usually do my own ph down with pure/high concentration phosphoric acid. I leave it on a an air tight, dark container and havent noticed relevant changes after a couple days. But i will start measuring the ph from my container cus sometimes i do get some ph drift i thought was from salt buildup, maybe i was wrong.

[lightyear]

I thought mine was salt too, but I started noticing it with plain water for seed starting too.

[blowdout2269]

I’ve done a test like this. It was years ago.
I was geared more towards the organic solutions though.
I found that out of Vinegar, Lemon Juice, and Vitamin C Powder, VCP actually held the pH down the longest with the most consistancy.
The other two always had an upward drift within 24hrs.
I’ll have to see if I can find my notes on that.
Great info you’ve shared bud.
I’m currently almost out of VCP. So I will soon be checking the effectiveness of Citric Acid Powder.

[lightyear]

Can’t speak for powder myself, but the Indo PH solution (with citric acid) does, in fact, take half as much solution to adjust the same gallon of water/nutes as any of the other 3, but it also has the dreaded PH drift issue.

[blowdout2269]

See!
I just really want to know if there’s a difference in Vitamin C Powder and Citric Acid Powder.
Cuz last I checked, the VCP I use holds very well.
Interesting discussion bud.

[Cyr_grow]

Have you tried distilled white vinegar for pH down?

[Andrexl]

@blowdout2269

Vitamin C Powder

Gotta stand by here to see this,I also got some Vitamina C Powder

[blowdout2269]

Yeah, it dont hold worth a shit, lol.
Lemon juice about the same.

Hmm, maybe have to re-do this experiment for everyone.

[Cyr_grow]

Gotchya, i have no idea if it did or didn’t. Figured I’d throw it out there

[blowdout2269]

Oh yeah, I’ve done Apple Cider Vinegar before too.
Surprisingly it holds slightly better than white.

[lightyear]

Cider vinegar can attract pests, so watch for that

[hooddirt]

@lightyear

Cider vinegar can attract pests

very true, I use an open bowl to trap and drown kitchen pests

[blowdout2269]

Hmm, interesting.
I’ve never heard this. Not a problem before either.
What kinda pests?

[lightyear]

Gnats, fruit flies, midge flies, and sometimes house flies.

[blowdout2269]

@lightyear

is the only PH down I’ve found that truly holds a stable PH level for a week or more. I can set my reservoir and forget it for the week, aside from monitoring the water level.

Wait, hold up.

But you have other factors at play here, dont you?

The roots are living in this water that’s being cycled back and forth.
Oxygen is entering the system at will.
(O2 will change pH values)
The plant(s) is up taking different nutrients all the time, isn’t it?
Nutrient uptake also changes the TDS(ppm/EC, whatever, lol) in the res. Which in turn can mess with the pH values, can it not?

Just thinking out loud here!

[blowdout2269]

Oh.
Those won’t live with BTI in my soil.

[lightyear]

Well, if you take my statement literally, yes… you’re technically correct. But all I was saying is I don’t have to readjust because it’s drifted so far it’s out of range. Sure, if I start at, say, 5.5ph then by the end of the week I’m probably going to end up with 6.2 or so, reasonably. But I consider that an ok drift. That’s what I would personally just chalk up to nute uptake, plant wastes, etc.

The drift with those that need adjusting is much more drastic. Let’s use plain tap water for this example just to eliminate variable additives affecting anything. If my tap water PH starts at 8.0, and I adjust it to 5.5 PH, with DG in two days it will not change. It still reads 5.5 PH. The other 3 (GH, Indo and AN) all will drift back to somewhere from 7.0-8.0 PH in the same two days with the same tap water. Just plain tap water. DG holds it stable, the rest do not. I personally can’t find any way to argue that could be caused by anything but the difference in ingredients. I see nothing else among them that tells me they’re different in any other way.