Sodium Hydroxide(NaOH) for Alk & pH

[ReyDeFarts]

I am curious if anyone here is using the recipe(s) suggested by folks like Randy Holmes-Farley for using Lye or Sodium Hydroxide (NaOH). Although it is possible to make your own solution from commonly available powder, I have access to 50% Caustic Soda. I created my own diluted solution tonight to do some testing. But I was wondering if anyone else here is dosing NaOH instead of traditional alk solutions.

I have to do additional programming on the Apex and DOS. I still need to figure out how much alk is being consumed by the system. Then I need to calculate the amount of alk per mL of the solution. It would not be precise, but a close enough calculation will get figured out soon.

This potentially will also offer a pH boost. What I don't know yet is if it will find equilibrium, similar to what happens with kalk dosing when it's dialed in. Or if I will have to stop the doser before it has dosed enough to give me the required alk. I currently have the DOS to turn off if the pH > 8.3.

I haven't programmed the actual volume to dose during the day yet. That's next.

 

[Darkxerox]

I wouldn't use it just because of the risk of you getting a leak in your tubing or container or having something happen along those lines. There's also the chance of having it splash into your eye by accident during prep (we don't touch it without face shields and full PPE). I think it's exothermic too so another thing to be careful while mixing.

Then there's the potential precipitation effect of CaCO3 and MgCO3 where it drips into the sump which @Alexander1312 is fully aware of.

But it's going to be really effective at raising your pH if that's your final goal.

 

[Coral reefer]

Also not a fan of relying on a ph probe staying calibrated

 

[JVU]

I don’t dose with it, but lots of people do.

Regarding the effect on pH, it’s the same ratio of pH effect relative to how much alkalinity you are adding compared with kalkwasser CaOH2. So you’ll get the same boost as you would with kalkwasser as an alkalinity additive. You can make NaOH much stronger concentration, which is an advantage but also what makes it much more dangerous, both outside your tank and inside, unless you are super careful.

The danger to people and pets is because it is very caustic, which is generally more dangerous to living tissue than strong acids. Very seriously dangerous at high concentrations, so having it going through tubing with connectors etc, and having to refill with possible splashing or spilling, it’s just too much risk for the benefit in my opinion. It also melts polycarbonate, so be careful there too.

The risk in tank is mostly just that since it’s so much more concentrated than kalkwasser, every drop makes a highly caustic little sphere of super high pH before it disperses, so more likely to damage something living or equipment, and more likely to precipitate out Ca or Mg, though that effect is temporary because it generally goes back into solution relatively quickly.

Not a risk, but another consideration is that it’s alk-only so if you use it with CaCl you’ll slowly raise your NaCl (salinity) as the Ca and carbonate get used. Unless you use the Balling type method with another additive to compensate.

Regarding transitioning from a different alk additive, the easiest and safest way is to dose both for a transition period, slowly decrease the old while increasing the new. Requires a free dosing head, but takes the stress out of it.

 

[H2OPlayar]

Soda ash (sodium carbonate) gives a ph bump relative to baking soda (sodium bicarbonate) and has worked great for me over the years without the worry about keeping a super caustic solution around.

 

[ReyDeFarts]

Regarding the dangers of this chemical, I work with 50% NaOH daily. So PPE is a must and understood. Maybe I'm not as worried about it because I'm around it so much everyday.

The diluted solution was 1:10 100mL 50% NaOH/1000mL RODI

@Darkxerox it is an exothermic reaction. It's actually safer to mix the 50% versus the powdered version that is shared in the recipes on R2R. Slow and steady mix and I barely got a reaction over 85°

But it's going to be really effective at raising your pH if that's your final goal.

Not the only goal. Utilizing it to maintain Alk would be #1 while also providing a pH boost.

Also not a fan of relying on a ph probe staying calibrated

Me neither. But I ensure they stay calibrated to have a bit of confidence. I also have dual probes setup. My goal was to determine alk consumption and dose to maintain alk, not necessarily pH. Only programmed it to ensure it at least stops if it hits 8.3.

Regarding the effect on pH, it’s the same ratio of pH effect relative to how much alkalinity you are adding compared with kalkwasser CaOH2. So you’ll get the same boost as you would with kalkwasser as an alkalinity additive.

That's what I thinking but I wasn't positive.

Not a risk, but another consideration is that it’s alk-only so if you use it with CaCl you’ll slowly raise your NaCl (salinity) as the Ca and carbonate get used. Unless you use the Balling type method with another additive to compensate.

Yeah, this is where I am a little stuck because I have not transitioned away from the AFR. But what you mentioned is the likely path and manually adding traces.

My thought was to see how much of this could be used daily to account for the alk consumption.

Soda ash (sodium carbonate) gives a ph bump relative to baking soda (sodium bicarbonate) and has worked great for me over the years without the worry about keeping a super caustic solution around.

Indeed. That was something I am still considering as well.

 

[JVU]

Regarding the dangers of this chemical, I work with 50% NaOH daily. So PPE is a must and understood. Maybe I'm not as worried about it because I'm around it so much everyday.

The diluted solution was 1:10 100mL 50% NaOH/1000mL RODI

Yeah I’m not personally too worried about it because I am very familiar with the required safety precautions and have experience with it for other uses. But I just wanted to point out that handling it in discrete intervals with full attention paid is different than having it run unattended for years through potentially long lengths of tubing with multiple junctions and failure points. Sounds like you understand the risks well.

 

[Alexander1312]

Brute force method for PH - don't do it (tried to not comment but had to, for the record and so...).

 

[ReyDeFarts]

Brute force method for PH - don't do it (tried to not comment but had to, for the record and so...).

Read again...lol. It's not just for pH. It's for Alk maintenance. The pH boost is an added benefit though.

But I just wanted to point out that handling it in discrete intervals with full attention paid is different than having it run unattended for years through potentially long lengths of tubing with multiple junctions and failure points.

No no, very good point. Everything can be going great until it isn't. You are definitely correct. Perhaps making a good SOP for line maintenance/ replacement and general head cleaning would be a good idea. I was reading a lot of input from users on R2R and they definitely have great success with it. This stuff gets thrown away and I know I can utilize it safely, even though it is not a traditional supplement that most reefers use. But definitely keeping in mind, the danger in and out of the tank is important to not be complacent.

 

[Alexander1312]

Read again...lol. It's not just for pH. It's for Alk maintenance. The pH boost is an added benefit though.

So you are saying. But PH is all we care about .