Rising alkalinity after pegging pH at 8.3

[Shooter6]

If you want to use KOH (or NaOH or KCl), I'd use food grade.

Says food grade.

 

[Shooter6]

I just don't see it being sensible. There's zero reason to tie potassium dosing and alkalinity dosing together.

Adding 1.4 dKH (0.5 meq/L) of alk a day via potassium hydroxide will boost potassium by 28 ppm.

That's a massive potassium boost for a normal alk boost, and is why folks cannot use just KOH.

But why use any KOH at all? Why not just add whatever alk you want by whatever method (including sodium hydroxide, which is no more expensive and can be more potent than KOH, if that matters) and then use cheap food grade KCl for the exact potassium boost you want?

But this is just theory until it's actually tested dont you agree? I mean if some individuals are having great success with it, and supposedly dosing way less then they were with kalk,calcium reactor,3 part, then there has to be something more to it then just the numbers that have been believed to be the standard. Discovery and new scientific findings are made by testing once believed truths and finding they are outdated and wrong all the time.

All I can say is I've never tried it, but I do find it interesting the results those who have tried it are reporting

 

[arking_mark]

But this is just theory until it's actually tested dont you agree? I mean if some individuals are having great success with it, and supposedly dosing way less then they were with kalk,calcium reactor,3 part, then there has to be something more to it then just the numbers that have been believed to be the standard. Discovery and new scientific findings are made by testing once believed truths and finding they are outdated and wrong all the time.

All I can say is I've never tried it, but I do find it interesting the results those who have tried it are reporting

It's called anecdotal evidence and is many times just snakeoil. In this case, easily debunked by basic seawater chemistry.

 

[Shooter6]

It's called anecdotal evidence and is many times just snakeoil. In this case, easily debunked by basic seawater chemistry.

So your saying their dosing amount has not gone down since they switched to potassium hydroxide while coral growth increased or at least didn't change? What benefits would they get by claiming it has?

That is why people who never tried it should not make definitive statements, just like kalk slurry is now catching on. Back in the day kalk slurry was considered an instant nuke of the tank.

 

[uninformed]

But this is just theory until it's actually tested dont you agree? I mean if some individuals are having great success with it, and supposedly dosing way less then they were with kalk,calcium reactor,3 part, then there has to be something more to it then just the numbers that have been believed to be the standard. Discovery and new scientific findings are made by testing once believed truths and finding they are outdated and wrong all the time.

All I can say is I've never tried it, but I do find it interesting the results those who have tried it are reporting

No, what he is saying is that dosing KOH unnecessarily causes you to add too much K to to get the pH and alkalinity benefit you want from the OH part of the salt. You can very easily and independently feed KCl for the K and NaOH for the OH to meet two unrelated goals.

It is similar to using kalk in your ATO. People do it, sure, but why limit your calcium and alkalinity dosing to your evaporation rate? Worse, why would you overdose both because you have a high evaporation rate? Why, when you can add and, more importantly, control them independently by dosing kalk separate from your ATO?

You dose “less” because you are feeding a lower volume of a higher strength solution, not because you have found some magical answer. CaOH has very limited solubility compared to KOH or NaOH, thus the reason you have to feed more of it for the same alkalinity impact. If I gave you five marbles in a zip-loc bag or I gave you five marbles in a trash bag, you still get five marbles, right? One is just a lot more easy and convenient to carry around.

 

[Randy Holmes-Farley Verified Community Expert]

But this is just theory until it's actually tested dont you agree? I mean if some individuals are having great success with it, and supposedly dosing way less then they were with kalk,calcium reactor,3 part, then there has to be something more to it then just the numbers that have been believed to be the standard. Discovery and new scientific findings are made by testing once believed truths and finding they are outdated and wrong all the time.

All I can say is I've never tried it, but I do find it interesting the results those who have tried it are reporting

Not sure what you are suggesting, but there are absolutely established chemical facts that are not open to debate. The main one in question here is whether KOH does anything different than NaOH and KCl when added to seawater. The answer is that it cannot cause a different effect and in my opinion, KOH is a poor way to attain these effects (regardless of what they may be). Doesn't mean it cannot work, just that it is not the best way to do it.

I'm open to unnaturally high potassium levels causing any possible effect.

But dosing potassium hydroxide as a way to attain high potassium and high pH and boost alkalinity seems limiting to me since you cannot control the alk and pH and potassium levels independently that way. You just get what you get.

I'd put the onus back on those suggesting it: why use KOH at all?

That said, if folks choose to use KOH and get a long term effect they want, I'm certainly not suggesting it cannot happen. I just think a little chemical understanding can improve the approach to give users a lot more control without sacrificing any possible benefits.

 

[Randy Holmes-Farley Verified Community Expert]

That is why people who never tried it should not make definitive statements, just like kalk slurry is now catching on. Back in the day kalk slurry was considered an instant nuke of the tank.

Have you ever walked on the moon? No? So you should not make any definitive statement suggesting having a spacesuit is better than not having one?

All people, whether scientists or not, should be open to new ideas and interpretations. That's how science works. I certainly consider myself open to ideas, and I always approach things in a very Darwinian way where the better ideas will win out over the poorer ideas.

But not all things are equally likely from first principles.

 

[arking_mark]

So your saying their dosing amount has not gone down since they switched to potassium hydroxide while coral growth increased or at least didn't change? What benefits would they get by claiming it has?

That is why people who never tried it should not make definitive statements, just like kalk slurry is now catching on. Back in the day kalk slurry was considered an instant nuke of the tank.

Bad analogy. Since as long as I have been reefing (20+ years), people have been trying to get more out of kalkwasser. We chemically know what it does and the limits of dosing saturated kalkwasser to your evaporation limit which is often not enough to meet your tank's demands. Many add vinegar to increase solubility and many have tried dosing slurry over the years. The issues has always been finding a reliable, accurate, and tank-safe way to do it.

 

[Miami Reef]

@Nerdist Aquarist

Did any acros die from the alk swing?

 

[Nerdist Aquarist]

@Nerdist Aquarist

Did any acros die from the alk swing?

My WWC Yellow Tip colony has some RTN running through the base, but I can't 100% attibute that to the Alk. It was showing stress before when I changed my light spectrum and intensity, it had lost the yellow color in the tips before the pH change. Other than that all across are fine so far.

 

[Miami Reef]

My WWC Yellow Tip colony has some RTN running through the base, but I can't 100% attibute that to the Alk. It was showing stress before when I changed my light spectrum and intensity, it had lost the yellow color in the tips before the pH change. Other than that all across are fine so far.

I’m stunned! I’m so glad you didn’t lose anything.

What’s your alk right now?

 

[Nerdist Aquarist]

I’m stunned! I’m so glad you didn’t lose anything.

What’s your alk right now?

Today's high was 10.7. I did back off the dosing a slight amount to peg a low pH of 8.2. I'd like to see Alk back down to 10 before I start ramping up again.

 

[Nerdist Aquarist]

The conversation has mainly been focused on corals, but it will be interesting to see how long I can go until the next fish mortality.

 

[ncjeepguy75]

It's an OK product (although of unknown purity). It's the claim about it pegging the aquarium at pH 8.3 that is incorrect.

It does not do that. The kernal of truth around that misleading claim is that when added to seawater, it tugs the pH toward 8.3 (whether that is up or down). It's just a mix of mostly bicarbonate and a little carbonate that does that.

But most people do not get as much pH boost as they want from it, and do not get a steady pH 8.3. They would be better off with a pure carbonate supplement, or best yet in terms of pH boost, hydroxide.

@Randy Holmes-Farley right on...I did a little test as I needed a bump in both pH and Alk...using your recipe for NaOH Sodium Hydroxide, I pared it down to a small batch (from 283g / gallon ==> 17g / 8 oz) and dosed that resulting solution in increments of 10ml over the course of a day or so...My results were for every 20ml of solution dosed, the pH increased by .1...I decided to take a final Alk reading after I reached a pH of 8.3 (coming from 7.7) and the resulting Alk was 11.25 dKH (coming from 9.96 dKH) ...I ended up dosing 130 ml of solution...now for the observation by eye...my corals are opening A LOT more than at the 7.7 pH and no real impact to fish or inverts...water appears much clearer and settles faster when my goby does its job...now the days after dosing like that the pH is hovering around 7.9 which is not too terribly bad and the Alk is staying around the 11 dKH mark as my tank uses about .25 dKH per day...So I agree that no product really targets and keeps the pH in place at a set value, especially without an impact to Alk...I also had been reading your articles and feel that with that lower pH that seems to be my tank average, that my Alk will need to be on the higher end to allow for higher uptake by corals to compensate for the lower pH....I really enjoy reading and discovering with everyone on these types of topics!...Helps me in my own reef battles!

 

[arking_mark]

@Randy Holmes-Farley right on...I did a little test as I needed a bump in both pH and Alk...using your recipe for NaOH Sodium Hydroxide, I pared it down to a small batch (from 283g / gallon ==> 17g / 8 oz) and dosed that resulting solution in increments of 10ml over the course of a day or so...My results were for every 20ml of solution dosed, the pH increased by .1...I decided to take a final Alk reading after I reached a pH of 8.3 (coming from 7.7) and the resulting Alk was 11.25 dKH (coming from 9.96 dKH) ...I ended up dosing 130 ml of solution...now for the observation by eye...my corals are opening A LOT more than at the 7.7 pH and no real impact to fish or inverts...water appears much clearer and settles faster when my goby does its job...now the days after dosing like that the pH is hovering around 7.9 which is not too terribly bad and the Alk is staying around the 11 dKH mark as my tank uses about .25 dKH per day...So I agree that no product really targets and keeps the pH in place at a set value, especially without an impact to Alk...I also had been reading your articles and feel that with that lower pH that seems to be my tank average, that my Alk will need to be on the higher end to allow for higher uptake by corals to compensate for the lower pH....I really enjoy reading and discovering with everyone on these types of topics!...Helps me in my own reef battles!

With an Alk of 11 and a 7.9 pH, your tank CO2 levels would be around 1500.

If your tank is well aerated and your not dosing something that would lower pH, then your main source of CO2 is your air...and would be at roughly 1500ppm.

It's possible, but unlikely that your air would be that high in CO2.

This would indicate that your measurements may be off.

This would also be true for the 7.7 pH you measured.

Unfortunately, our hobby-grade test kits and meters just aren't that accurate.

 

[ncjeepguy75]

With an Alk of 11 and a 7.9 pH, your tank CO2 levels would be around 1500.

If your tank is well aerated and your not dosing something that would lower pH, then your main source of CO2 is your air...and would be at roughly 1500ppm.

It's possible, but unlikely that your air would be that high in CO2.

This would indicate that your measurements may be off.

This would also be true for the 7.7 pH you measured.

Unfortunately, our hobby-grade test kits and meters just aren't that accurate.

@arking_mark Thanks for your input....It would not surprise me about the CO2...Our house is super well insulated and when the windows are closed pretty much air tight (windows rattle and you feel air movement when you open and close a door) yesterday we had a nice 75 degree day here in NC and I opened all of our windows and guess what????...pH slowly increased throughout the day without me dosing anything...went from 7.7 to 8.0 in a matter of about 6 hours...now yes, I turned on all fans and even the fans in the HVAC unit to assist with exchanging house air with outside air!...I agree though our hobby test kits just get us in the ballpark.

 

[ncjeepguy75]

@arking_mark Thanks for your input....It would not surprise me about the CO2...Our house is super well insulated and when the windows are closed pretty much air tight (windows rattle and you feel air movement when you open and close a door) yesterday we had a nice 75 degree day here in NC and I opened all of our windows and guess what????...pH slowly increased throughout the day without me dosing anything...went from 7.7 to 8.0 in a matter of about 6 hours...now yes, I turned on all fans and even the fans in the HVAC unit to assist with exchanging house air with outside air!...I agree though our hobby test kits just get us in the ballpark.

@arking_mark that does make sense though...we have a 220 gallon freshwater planted tank downstairs that we pump CO2 into for the plants....so there is the rest of the story!

 

[e34stx]

Today's high was 10.7. I did back off the dosing a slight amount to peg a low pH of 8.2. I'd like to see Alk back down to 10 before I start ramping up again.

how much are you dosing and for what size tank?

 

[Morpheosz]

With an Alk of 11 and a 7.9 pH, your tank CO2 levels would be around 1500.

If your tank is well aerated and your not dosing something that would lower pH, then your main source of CO2 is your air...and would be at roughly 1500ppm.

It's possible, but unlikely that your air would be that high in CO2.

This would indicate that your measurements may be off.

This would also be true for the 7.7 pH you measured.

Unfortunately, our hobby-grade test kits and meters just aren't that accurate.

Sorry to revive an old thread, but I'm wondering what tool you use to calculate the CO2 in the air as you did here. I am curious given a ph of 7.9 and a dkh of 8.2 (my readings this morning), curious what the math says that the CO2 is in the house and whether or not it jives with what I've measured.. more on that...

I'm running a pretty consistent 8dkh, and a recirculating scrubber on an appropriately sized skimmer (Essence S-130 on 95g volume) and my ph rarely gets above 8.2. For a number of weeks I was content with a night-day range of ~8.05 - 8.15, but in the last couple days it's dropped for no apparent reason. Last night down to 7.9, today's high was only 8.06. I bought a CO2 monitor off Amazon awhile back and my basement where the sump is reads ~600-650PPM and my office where the tank is ranges from 700 overnight to 1200 worst case if I'm in here for a couple hours with the door shut. However, I should think the overall environment the tank water is exposed to probably averages 600-800ppm. I feel like I should be getting higher pH given good aeration and the scrubber. Prior to the scrubber I was in the 7.7-7.9 range daily.

 

[arking_mark]

Sorry to revive an old thread, but I'm wondering what tool you use to calculate the CO2 in the air as you did here. I am curious given a ph of 7.9 and a dkh of 8.2 (my readings this morning), curious what the math says that the CO2 is in the house and whether or not it jives with what I've measured.. more on that...

I'm running a pretty consistent 8dkh, and a recirculating scrubber on an appropriately sized skimmer (Essence S-130 on 95g volume) and my ph rarely gets above 8.2. For a number of weeks I was content with a night-day range of ~8.05 - 8.15, but in the last couple days it's dropped for no apparent reason. Last night down to 7.9, today's high was only 8.06. I bought a CO2 monitor off Amazon awhile back and my basement where the sump is reads ~600-650PPM and my office where the tank is ranges from 700 overnight to 1200 worst case if I'm in here for a couple hours with the door shut. However, I should think the overall environment the tank water is exposed to probably averages 600-800ppm. I feel like I should be getting higher pH given good aeration and the scrubber. Prior to the scrubber I was in the 7.7-7.9 range daily.

There is a mathematical model for pH, Alk, and CO2. I use the pyCO2SYS python library to do the calculations.

Given an 8.2dKH and a pH of 7.9 NBS, a perfectly aerated tank at equilibrium with the air would expect an air CO2 of 1100ppm.

Given an 8dKH and air CO2 of 700ppm, a perfectly aerated tank at equilibrium with the air would expect a pH of 8.07.

Take all of this info with the understanding that our hobby-grade measurement are not very accurate...I've most often seen pH issues really being measurement issues.