Kalk vs hydroxide PH elevating boost

[Saltyanimals]

Thanks Randy for double checking the recipe. I must have misunderstood the recipe calculation as I borrowed from your DIY 2 part NaOH. Since I did 1/3 with my current 73.5 g/L. I will instead increase to 220.5 g/L.

I was also surprised at the 0.1 pH boost given such a small liquid amount. I was careful to not change anything else. No windows open, no changes to tank. That's why the caveat highlighting it's only a 10 day sample. However the daily logs are very stable where I could predict the next test window values and be very close. That's why I stopped at 10 days to do something different.

I'll start the new 220.5 g/L recipe and report back after another 7-10 days.

 

[Randy Holmes-Farley]

Thanks Randy for double checking the recipe. I must have misunderstood the recipe calculation as I borrowed from your DIY 2 part NaOH. Since I did 1/3 with my current 73.5 g/L. I will instead increase to 220.5 g/L.

I was also surprised at the 0.1 pH boost given such a small liquid amount. I was careful to not change anything else. No windows open, no changes to tank. That's why the caveat highlighting it's only a 10 day sample. However the daily logs are very stable where I could predict the next test window values and be very close. That's why I stopped at 10 days to do something different.

I'll start the new 220.5 g/L recipe and report back after another 7-10 days.

THe standard DIY recipe is given here:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

It is: Add 283 grams of sodium hydroxide to 1 gallon of fresh water.

Then you can use this calculator and the entry for Randy's recipe #1 to get the alk boost from any given addition:

Reef Chemistry Calculator

I do not recommend making it extra strong unless there's an important reason to do so. It will be harder to disperse rapidly if more concentrated, which may make precipitation of calcium carbonate more likely.

Using the standard recipe, 1 mL in 180 gallons boosts alk by 0.008 dKH.

 

[Saltyanimals]

I rechecked my notes and you're right. I misstated. I was mixing 110g of NaOH to 1000 ml. Your recipe at 1.5x would have been that same 110g however to 946ml instead. I did it slightly less so not a full 1.5x as I read others did in that DIY mix thread.

However the dosing frequency and amounts (24ml daily) I stated earlier still yielded those results which is a bit puzzling.

Taking as step back to your recipe for a sanity check! Looking at your link and the dosing calculator I see:

I read that as raising 0.1 dKh requires 12.8ml of the solution added. I would add that 12.8ml over 24 hours which would be very little 0.5ml hourly using the standard (1x) recipe.

If I was to do the above 3x. Wouldn't I expect 0.3 dkH raise for the same 12.8ml? I'm dosing right into the return pump chamber so hopefully that'll quickly max and minimize the precipitation that you warned about.

 

[mudbugmike]

snip

I think it is difficult to measure the exact dkh/ph boost because the alkalinity dose isn't the only variable.

I have shifted my dosing (283g in 1 gallon) from 24ml (6x 4ml doses) to 36ml (24 doses. alternating 1 and 2ml every other hour). to adjust to the alk consumption. With this change, I went from a ph of 8.0-8.3(on a good day doors open) to banging on 8.5's door. Still running about 9dkh and co2 scrubbing.

Once my ph started to get up to 8.2 I really started to notice a dramatic difference in the dosing required to keep up.

 

[Saltyanimals]

I think it is difficult to measure the exact dkh/ph boost because the alkalinity dose isn't the only variable.

I have shifted my dosing (283g in 1 gallon) from 24ml (6x 4ml doses) to 36ml (24 doses. alternating 1 and 2ml every other hour). to adjust to the alk consumption. With this change, I went from a ph of 8.0-8.3(on a good day doors open) to banging on 8.5's door. Still running about 9dkh and co2 scrubbing.

Once my ph started to get up to 8.2 I really started to notice a dramatic difference in the dosing required to keep up.

You're exactly right on the too many variables part. I'm trying to keep all those variables constant for now while I'm running this little experiment. Maybe in the near future I'll raise my running alk from 8.5 to 9.5 to further shift on the alk to ph curve that Randy reshared. While I'm already on the low pH curve, it should give give me that extra higher starting pH point. Without any changes since I report above, I'm starting to see my newly celebrated pH gains starting to deteriorate a bit. Alk still rock solid day over day within 0.01 from the previous reading.


What is your total water volume? I considered going your route with less frequency but more volume when I considered how little solution was actually added. I'm trying to limit my dosing to the 24-36ml daily myself to minimize mixing maintenance thus the higher potency experiment. I could also try dosing only at nights as I've ready some kalk dosers use that strategy to keep the pH up and less for it to climb during the lighting period.

 

[mudbugmike]

You're exactly right on the too many variables part. I'm trying to keep all those variables constant for now while I'm running this little experiment. Maybe in the near future I'll raise my running alk from 8.5 to 9.5 to further shift on the alk to ph curve that Randy reshared. While I'm already on the low pH curve, it should give give me that extra higher starting pH point. Without any changes since I report above, I'm starting to see my newly celebrated pH gains starting to deteriorate a bit. Alk still rock solid day over day within 0.01 from the previous reading.


What is your total water volume? I considered going your route with less frequency but more volume when I considered how little solution was actually added. I'm trying to limit my dosing to the 24-36ml daily myself to minimize mixing maintenance thus the higher potency experiment. I could also try dosing only at nights as I've ready some kalk dosers use that strategy to keep the pH up and less for it to climb during the lighting period.

72g display 19g sump I think (reefer 350)

 

[Saltyanimals]

6 days later under the 3x strength (849g per 1 gallon). Doing the same 24ml total daily (24 x 1ml hourly). General observations:

- Alk increased as expected since the potency is now stronger
- pH Affect - continues positive boost to pH, however very little to no changes in pH graphs between the 1x strength to 3 x strength as I study the graphs and tables over the past couple weeks. **
- My pH seems more impacted by the CO2 in the air with more/less people in the house at certain days

** This seems to echo what Randy said earlier about pH affect as a result of the dosing. Same dose amount of liquid doesn't seem to move the pH between solution concentration. What this tells me is that I need to play with the dosing volume amount and timing as @mudbugmike did to realize his changes. He did a 50% increase in volume which I'm about to do myself in the next couple days. more volume = more pH affect.

Will report back.

 

[Saltyanimals]

Another 6 day later update. I continued the same 3x solution however increased to 36 ml/daily this time as @mudbugmike did. General observations:

- I saw my tank pH hit 8.1 for the first time ever. Seems to move right around here so I'm not expecting it to go much higher.
- However looking back through my logs and apex graphs through a more critical eye, I didn't see much difference between the 3x and 1.5x solution from a pH effect perspective. The graphs ticked upwards over time, but could that be just a gradual expected rise as the tank rebalanced? Yes I hit my magical 8.1 for my tank, but did not see a clear jump between solution changes relative to doubling the NaOH. This refill will last about a month which I may scale back down to 1.5x potency when I refill next to see how it impacts the pH. My theory is minimum impact between the two solutions so not worth the extra impact to tubing, mixing, etc to justify the effort if it yields the same pH results. This is focused on pH only so Alk benefits aside for now.
- the 0.1 total pH bump seems to be consistent as the high-lows shift upwards, but I would say this is the high end of the benefits. Still a winner for my tank given the the numerous pH inhibitor's I have in the biopellet, CaRX and tight house.


I'll let this ride out in a do-nothing mode for another week before I try and squeeze more pH out of other things in my tank. Will take another round at tuning my CaRx again to further reduce pH effluent. Will also move the effluent tube to the skimmer intake. I see this as my NaOH experiment final lap after this 3 week short experiment. Will report back if things change dramatically.

 

[Saltyanimals]

Another update 9 days later.

There is clear evidence from my graphs that NaOH is a big contributor to my pH boost. I did spend a little time to tighten up my CaRX tuning to gain some pH there. It did help which brought my new range to 7.8x to almost 8.17. See the graph below. It stayed here for days which shows increasing stability into this new elevated pH range for me. The combination of my CaRX and 3x NaOH solution was adding 0.5 dKh too much daily so I turned off my NaOH doser for exactly 24 hours. Since it was contributing approx 0.5 dkH, this should drop it by that 0.5.

Sure enough.. dKh dropped it almost exactly 0.5 as expected, but check out the pH tank down to 7.52 with it off. I turned it back on a few hours after this bottom and you can see the graph starting to stabilize again.

The take away here so that NaOH will stay as a big part of my balanced Alk/CA and pH combo. I'll continue to dial the CaRX down. My effluent is currently 30 dkH so room to play there. I should see the pH continue upwards as shown in the graph before I stopped the NaOH. Since it plays such a big part of the pH equation, I can't afford to touch the NaOH.

 

[Saltyanimals]

Update 1 month later.

I've continued over this past month making various changes and keeping a log, I've come to the following conclusions for my tank as all tanks are different. Sharing for anyone else that may go down this path.

- Watch your Ca if you're not doing a balanced solution. For me, I backed down my CaRX significantly allowing the NaOH to serve as the majority of the Alk provider. Doing so, my Ca dropped over time as I was doing only a NaOH + Rodi mix. I forgot all about the Ca as I don't test this often. When I did, it was in the 320s. I quickly adjusted, but lessons learned for other people to not fall into this mistake if you're backing off CaRX.
- I did 1.5x and 3x concentration and my take away is that the 3x will give a slight pH boost over 1.5x, but not signficant to warrant the extra NaOH powder. What is more important is the volume per single dose and frequency relative the your water volume. Running 3x solution was actually too strong which forced me to back down from the CaRX. See above for Ca impact.
-Moving back to a 1.5x solution allows me to dose a higher volume per day which had a better overall pH boost. Even this is too strong and I'm now running NaOH only at nights otherwise my Alk will run away. I may return to a 3x solution if I find myself dosing too much CaRX which has the inherit pH depression with low pH effluent. It's a balancing game.


Next steps for me
- Keeping the current regime and as my consumption goes up as it should, I'll increase the NaOH schedule so I'm not dosing only at nights. This should give me a pH boost along the way.
- Will leave my CaRX locked in for now in a conversative volume

My new pH range is 7.8 low in the mornings to 8.0 at the peak high. Nothing to win pH competitions, but it is a 0.2 increase that I attribute to the NaOH and also tuning my CaRX more tightly. Note I suffered from severe low pH as low as 7.5s so having a 7.8 bottom is a winner. I see this range going up over time naturally as I tune to keep up with demand.

 

[Randy Holmes-Farley]

Update 1 month later.

I've continued over this past month making various changes and keeping a log, I've come to the following conclusions for my tank as all tanks are different. Sharing for anyone else that may go down this path.

- Watch your Ca if you're not doing a balanced solution. For me, I backed down my CaRX significantly allowing the NaOH to serve as the majority of the Alk provider. Doing so, my Ca dropped over time as I was doing only a NaOH + Rodi mix. I forgot all about the Ca as I don't test this often. When I did, it was in the 320s. I quickly adjusted, but lessons learned for other people to not fall into this mistake if you're backing off CaRX.
- I did 1.5x and 3x concentration and my take away is that the 3x will give a slight pH boost over 1.5x, but not signficant to warrant the extra NaOH powder. What is more important is the volume per single dose and frequency relative the your water volume. Running 3x solution was actually too strong which forced me to back down from the CaRX. See above for Ca impact.
-Moving back to a 1.5x solution allows me to dose a higher volume per day which had a better overall pH boost. Even this is too strong and I'm now running NaOH only at nights otherwise my Alk will run away. I may return to a 3x solution if I find myself dosing too much CaRX which has the inherit pH depression with low pH effluent. It's a balancing game.


Next steps for me
- Keeping the current regime and as my consumption goes up as it should, I'll increase the NaOH schedule so I'm not dosing only at nights. This should give me a pH boost along the way.
- Will leave my CaRX locked in for now in a conversative volume

My new pH range is 7.8 low in the mornings to 8.0 at the peak high. Nothing to win pH competitions, but it is a 0.2 increase that I attribute to the NaOH and also tuning my CaRX more tightly. Note I suffered from severe low pH as low as 7.5s so having a 7.8 bottom is a winner. I see this range going up over time naturally as I tune to keep up with demand.

Thanks for the update!

 

[Saltyanimals]

Okie dokie. It's been 2 months since my last update here and I think I've hit the proverbial wall on NaOH benefits. In hindsight, I think the NaOH as 2 or 3 part alk replacement would be outstanding , but maybe not so much for my use case: getting the ph boost.

And here's why IMHO for others

- It's not a balanced Alk + CA like Kalk is. It is only Alk. Which if you follow my journey above, it causes my Ca to drift downwards since my balanced solution is the CaRX which I turned down a few notches to "make room" for the NaOH providing stronger alk. This made Ca go out of balance and required me to dose Ca separately. Since CA stability is not critical to coral, I was okay with dosing it weekly along with my weekly cocktail of trace.
- The pH boost is there, but I think I've topped out of the pH boost. I will inch towards 8.1 which is unheard of in my tank and worth dancing.. but the NaOH solution required to get there will require a monthly refill which goes against my low maintenance goal.

What's next? ??

I'm considering going the Kalk reactor route to replace the NaOH dosing as supplemental to my CaRX. As I've read, I can simply dump in more kalk every 1-2 weeks and allow the reactor to stir and mix. Nothing for me to measure and mix by hand. Winner! Kalk is balanced Ca + Alk so eliminates the Ca drift as I mentioned above. Winner!


Question:

Would I get the same tank pH affects out of a saturated kalk reactor as I would based on the NaOH (283 g/gallon) for the same liquid volume? If the expected pH affect is the same, dropping a cup or so regularly into an auto mixing kalk reactor seems to be the winner.

 

[Randy Holmes-Farley]

Okie dokie. It's been 2 months since my last update here and I think I've hit the proverbial wall on NaOH benefits. In hindsight, I think the NaOH as 2 or 3 part alk replacement would be outstanding , but maybe not so much for my use case: getting the ph boost.

And here's why IMHO for others

- It's not a balanced Alk + CA like Kalk is. It is only Alk. Which if you follow my journey above, it causes my Ca to drift downwards since my balanced solution is the CaRX which I turned down a few notches to "make room" for the NaOH providing stronger alk. This made Ca go out of balance and required me to dose Ca separately. Since CA stability is not critical to coral, I was okay with dosing it weekly along with my weekly cocktail of trace.
- The pH boost is there, but I think I've topped out of the pH boost. I will inch towards 8.1 which is unheard of in my tank and worth dancing.. but the NaOH solution required to get there will require a monthly refill which goes against my low maintenance goal.

What's next? ??

I'm considering going the Kalk reactor route to replace the NaOH dosing as supplemental to my CaRX. As I've read, I can simply dump in more kalk every 1-2 weeks and allow the reactor to stir and mix. Nothing for me to measure and mix by hand. Winner! Kalk is balanced Ca + Alk so eliminates the Ca drift as I mentioned above. Winner!


Question:

Would I get the same tank pH affects out of a saturated kalk reactor as I would based on the NaOH (283 g/gallon) for the same liquid volume? If the expected pH affect is the same, dropping a cup or so regularly into an auto mixing kalk reactor seems to be the winner.

I’m not sure why you aren’t just using the two part recipe so you don’t have the calcium issues.

As to what does what, hydroxide doesn’t know where it came from, so the pH boost per unit of alk added is identical for NaOH and Ca(OH)2. All that matters is how much you add and at what rate.

Adding NaOH into limewater (kalkwasser) will reduce the solubility of the calcium hydroxide, so it is not just additive to potency, but less than additive.

 

[Saltyanimals]

Music to my ears! I’m just experimenting using the NaOH only portion of the 2 part for the pH boost benefits. I’m trying to never mix anything period. That’s why the question of one hydroxide vs another. Since you said the pH affect observed in the tank is the same between NaOH and kalk, the saturated kalk reactor is the winner. I’ll simply keep dumping in kalk powder into the reactor and never have to measure or mix anything manually.

This may be the end of my NaOH experiment. If I’m expecting the same pH benefit then I already know my expected pH range under Kalk is what I have today at 283 g/gallon NaOH.

 

[Randy Holmes-Farley]

Music to my ears! I’m just experimenting using the NaOH only portion of the 2 part for the pH boost benefits. I’m trying to never mix anything period. That’s why the question of one hydroxide vs another. Since you said the pH affect observed in the tank is the same between NaOH and kalk, the saturated kalk reactor is the winner. I’ll simply keep dumping in kalk powder into the reactor and never have to measure or mix anything manually.

This may be the end of my NaOH experiment. If I’m expecting the same pH benefit then I already know my expected pH range under Kalk is what I have today at 283 g/gallon NaOH.

OK, limewater (kalkwasser) is certainly a fine way to go. I used it alone for 20 years (from a settled reservoir, not a reactor).

But it has limitations, such as the daily evaporation limit.

 

[Saltyanimals]

Music to my ears! I’m just experimenting using the NaOH only portion of the 2 part for the pH boost benefits. I’m trying to never mix anything period. That’s why the question of one hydroxide vs another. Since you said the pH affect observed in the tank is the same between NaOH and kalk, the saturated kalk reactor is the winner. I’ll simply keep dumping in kalk powder into the reactor and never have to measure or mix anything manually.

This may be the end of my NaOH experiment. If I’m expecting the same pH benefit

 

[Randy Holmes-Farley]

Music to my ears! I’m just experimenting using the NaOH only portion of the 2 part for the pH boost benefits. I’m trying to never mix anything period. That’s why the question of one hydroxide vs another. Since you said the pH affect observed in the tank is the same between NaOH and kalk, the saturated kalk reactor is the winner. I’ll simply keep dumping in kalk powder into the reactor and never have to measure or mix anything manually.

This may be the end of my NaOH experiment. If I’m expecting the same pH benefit

I would not assume the reactor is producing saturated kalkwasser, but if it meets your alk demand, it’s good enough.