Aqua Man

Staff member
Supporter
But potassium bircarb is alkali, I'm having problems keeping it down
Yes I know. Here is what happens think of this way. You have very little alkalinity so it takes very little acid to bring the ph down. Now as the acid breaks down since there is so little the ph rises quickly. If you add more alkalinity you can add more acid to achieve the desired ph. So as the acid breaks down there is more of it and it takes longer for the ph to rise.

But having to much alkalinity causes you to have to add to much acid and can be bad. The key is finding a balance for a stable ph.

I gave you a very conservative amount to add so if anything you may need a bit more.

Does this make sense?
 

Aqua Man

Staff member
Supporter
Basically with a water source with low amount of carbonate or bicarbonate you will always have this problem no matter what acid you have. RO needs to have some added.
 

Aqua Man

Staff member
Supporter
Here's my ratios for veg mix:

NH4 = 2.8ppm
NO3 = 30.8 + 5.6 + 10.5 = 46.9 = 50totN (5.6%NH4)
P = 15.5 + 1.55 = 17ppm
K = 19.5 + 29.25 = 49ppm
Ca = 40ppm
Mg = 12 + 4.8 = 16ppm
S = 16ppm

Total: 188 ppm
N—P—K = 3—1—3
K—Ca—Mg = 3—3—1

My flower mix:

NH4 = 2.8
NO3 = 30.8 + 5.6 + 21 = 57.4 = 60totN (4.6%NH4)
P = 31 + 3.1 = 34
K = 39 + 58.5 = 98
Ca = 40
Mg = 24 + 4.8 = 28
S = 32

Total: 292 ppm
N—P—K = 2—1—3
K—Ca—Mg = 4—2—1
Ca-N = 0.91


After 2 years of messing around I've settled on these ratios
I feel like your ratios are good but ppm is to low.

I hit 1000ppm during stretch. Each system is different but that's kinda low.
 
Yes I know. Here is what happens think of this way. You have very little alkalinity so it takes very little acid to bring the ph down. Now as the acid breaks down since there is so little the ph rises quickly. If you add more alkalinity you can add more acid to achieve the desired ph. So as the acid breaks down there is more of it and it takes longer for the ph to rise.

But having to much alkalinity causes you to have to add to much acid and can be bad. The key is finding a balance for a stable ph.

I gave you a very conservative amount to add so if anything you may need a bit more.

Does this make sense?
I think you talking about creating a buffer system between a weak acid and a weak alkali, they used a lot in biology experiments. I have quite a bit of alkalinity in my water already you see, my pH is like 9. something. I have never had this problem before because I used ghe wich contains lots of phos acid and now my own stock solutions i make have phosphoric acid in already, but not enough. The pH stays rock solid with phos acid. I guess the natural carbonate levels counterbalances this and creates a chemical control system absorbing and relasing pH correcting protons when the pH deviates too far
 

Aqua Man

Staff member
Supporter
I think you talking about creating a buffer system between a weak acid and a weak alkali, they used a lot in biology experiments. I have quite a bit of alkalinity in my water already you see, my pH is like 9. something. I have never had this problem before because I used ghe wich contains lots of phos acid and now my own stock solutions i make have phosphoric acid in already, but not enough. The pH stays rock solid with phos acid. I guess the natural carbonate levels counterbalances this and creates a chemical control system absorbing and relasing pH correcting protons when the pH deviates too far
Ph doesn't mean you have carbonates it only shows the water is more base. You can't use ph to tell how much buffering capacity your water has. It's the carbonate hardness you need to find out 4-8dkh is ideal
 
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