low ph during vinegar dosing / solutions?

[skr791346]

Vinegar dosing is working great for me but I'm having issues with low pH throughout the day even after spreading the dose out. (Lowest at 7.85 and during peak photoperiod, only tops at 7.95 vs before I started vinegar dosing, pH always stayed between 8.01 to 8.15)

I read previous threads of adding kalkwasser to vinegar to counter the pH drop but I'm dosing ESV 2 part for Alk & Cal. Is it still ok to use kalkwasser in vinegar with ESV 2 part? Any other solutions to counter this issue of constant low pH?

 

[Randy Holmes-Farley Verified Community Expert]

Yes, you likely won’t add much calcium and alkalinity this way. You can determine how much if you tell me the daily vinegar and the tank volume.

 

[AdamNC]

Easiest was I found to keep pH up with carbon dosing is to run my skimmer air inlet through my wall to the outside. Has done wonders. 8.2 DTH and 8.0 NTL.

 

[skr791346]

Yes, you likely won’t add much calcium and alkalinity this way. You can determine how much if you tell me the daily vinegar and the tank volume.

Daily vinegar is 48.2ml, tank volume 150 Gallons (Spread out over 7 hours, should I spread it out more?) Currently dosing 17ml of ESV A&B daily. Thank you in advance, Randy

Easiest was I found to keep pH up with carbon dosing is to run my skimmer air inlet through my wall to the outside. Has done wonders. 8.2 DTH and 8.0 NTL.

Unfortunately, this is not an easy option for me but I do have the skimmer air intlet attached to a CO2 scrubber. Before vinegar, it helped significantly with pH but now, not enough.

 

[Randy Holmes-Farley Verified Community Expert]

50 mL of vinegar contains 2.5 grams (42 millimoles) of acetic acid. So if that is fully neutralized, it adds 42 milliequivalents of alkalinity to the tank. In 150 gallons (568 L), this is 42 meq/568 L = 0.074 meq/L = 0.2 dKH. Then there will be an very tiny amount of calcium hydroxide dissolved in the 50 mL.

Thus, the total alk and calcium added is small.

 

[skr791346]

50 mL of vinegar contains 2.5 grams (42 millimoles) of acetic acid. So if that is fully neutralized, it adds 42 milliequivalents of alkalinity to the tank. In 150 gallons (568 L), this is 42 meq/568 L = 0.074 meq/L = 0.2 dKH. Then there will be an very tiny amount of calcium hydroxide dissolved in the 50 mL.

Thus, the total alk and calcium added is small.

Relieved to read that the impact will be minimal on the Alk. How much calcium hydroxide should I be mixing into the vinegar dosing container? Do I just stir it and let it settle?

 

[Randy Holmes-Farley Verified Community Expert]

Relieved to read that the impact will be minimal on the Alk. How much calcium hydroxide should I be mixing into the vinegar dosing container? Do I just stir it and let it settle?

when I did it, I just added enough calcium hydroxide that after shaking a few minutes, some solids remained that settled to the bottom. Then use the mostly clear liquid on top.

 

[skr791346]

when I did it, I just added enough calcium hydroxide that after shaking a few minutes, some solids remained that settled to the bottom. Then use the mostly clear liquid on top.

To clarify, are you mixing your top off RODI water with kalkwasser & vinegar? Or mixing purely kalk and vinegar and dosing?

 

[Titolee]

To clarify, are you mixing your top off RODI water with kalkwasser & vinegar? Or mixing purely kalk and vinegar and dosing?

Was there ever an update on this? I am having the same issue with low PH while dosing NOPOX.

 

[Randy Holmes-Farley Verified Community Expert]

To clarify, are you mixing your top off RODI water with kalkwasser & vinegar? Or mixing purely kalk and vinegar and dosing?

I took the bottle of vinegar from the grocery store, and added dry calcium hydroxide to it, shook it up, let it settle, and manually dosed the clear liquid.

 

[Clownfishy]

Was there ever an update on this? I am having the same issue with low PH while dosing NOPOX.

I saw the same thing and I have now set my Apex DOS to dose NOPOX when my pH begins to rise in the morning after the lights being on. Also to stop dosing 5 hours before the lights go off. This seems to have helped the bigger drops in pH I observed before. Interestingly, I see a big ORP drop 1 to 1.5 hours after starting dosing NOPOX in the morning.

 

[Randy Holmes-Farley Verified Community Expert]

Was there ever an update on this? I am having the same issue with low PH while dosing NOPOX.

The same thing will work with NOPOX to prevent any immediate pH drop when dosing it, but all organic carbon dosing produces CO2 and thus causes a pH drop to some extent. Adding calcium hydroxide to NOPOX will not be as effective as to vinegar (and would be almost no use at all in vodka alone), but it is of some value in terms of pH.

 

[Clownfishy]

Here is the drop in ORP I mentioned shortly after NOPOX dosing begins in the morning

 

[Randy Holmes-Farley Verified Community Expert]

Here is the drop in ORP I mentioned shortly after NOPOX dosing begins in the morning

Can you clarify what we are looking at? When and where is ORP dropping and when did you dose the NOPOX?

 

[Clownfishy]

Can you clarify what we are looking at? When and where is ORP dropping and when did you dose the NOPOX?

Apologies, the phone screenshot was not perfect so here is a better picture. The DOS starts dosing NOPOX at 9:00am at 0.1ml every 13 minutes indicated by the blue lines. By 10:30am, I see the ORP drop by approximately 30 over 2 hours and then it starts to rise again. NOPOX is dosed until 16:00 and although I see the drop in ORP, my pH has improved when dosing NOPOX only when my pH is rising while the lights are on. Before this, I was dosing some of the NOPOX when my lights were off and pH low and that seem to keep my pH lower than I observe now.

 

[Randy Holmes-Farley Verified Community Expert]

Apologies, the phone screenshot was not perfect so here is a better picture. The DOS starts dosing NOPOX at 9:00am at 0.1ml every 13 minutes indicated by the blue lines. By 10:30am, I see the ORP drop by approximately 30 over 2 hours and then it starts to rise again. NOPOX is dosed until 16:00 and although I see the drop in ORP, my pH has improved when dosing NOPOX only when my pH is rising while the lights are on. Before this, I was dosing some of the NOPOX when my lights were off and pH low and that seem to keep my pH lower than I observe now.

ORP naturally falls as pH rises. Might that be the nature of the ORP change you are seeing?

 

[threebuoys]

I took the bottle of vinegar from the grocery store, and added dry calcium hydroxide to it, shook it up, let it settle, and manually dosed the clear liquid.

A friendly suggestion to those who might try this for the first time,

Buy vinegar in glass, not plastic bottles! I added calcium hydroxide to a plastic bottle of vinegar as Randy suggests and used it for a while. Then, I backed offon vinegar dosing while I tried to deal with some other problems. The calcium hydroxide in the bottom of the vinegar bottle ate a hole through the bottom of the bottle. Fortunately, I notice the leak before it all poured out! I should have known better. Probably put too much calcium hydroxide in the bottle.

 

[Randy Holmes-Farley Verified Community Expert]

Wow, I never had an issue with 1 gallon plastic jugs of vinegar from Stop and Shop.

Can you see a recycling code on the plastic bottle?

 

[threebuoys]

Wow, I never had an issue with 1 gallon plastic jugs of vinegar from Stop and Shop.

Can you see a recycling code on the plastic bottle?

I'll look the next time I go to the grocery store, food lion brand.The bottle was clear, fairly stiff plastic as opposed to the kind used for milk or orange juice

 

[Randy Holmes-Farley Verified Community Expert]

Mine was opaque and high density polyethylene (I think), which is perfect.