Saturation question

[Lycosa]

I was hoping someone could answer this for me.

In a liter of RO/DI water, how much Sodium Hydroxide can be saturated into solution?

How much Potassium Hydroxide?

Lastly, what will the alkalinity be at saturation for both?

(If you would demonstrate the math, that would be extra helpful.)

Thanks Much!

 

[Randy Holmes-Farley]

Both can be made very, very concentrated (more solids than water) and I do not recommend trying to dose such a solution.

 

[Lycosa]

Both can be made very, very concentrated (more solids than water) and I do not recommend trying to dose such a solution.

I understand the hazards associated with it. I didn't plan on getting extraordinarily concentrated. I had hoped that at saturation, it wouldn't be so potent. Can you recommend a less potent dose with an appreciable alkalinity? In grams/L.

*Edit*
I do understand the responsibility associated with giving advice on something that is inherently dangerous. I am not a chemist and further, I took chemistry in college and haven't used it in many years (other than the basics to do with reef keeping). That might make me more dangerous I suppose. I do not have any preconceived notions about my abilities. I know the information is out there already, but I thought I'd like to hear it from an aquarist's perspective. I just want something to extrapolate out into a less dangerous and still viable alkalinity solution. I had thought, seems I thought wrong, that it would precipitate out at a less potent concentration. Apparently, that's not the case. If even bringing up a 'recipe' is more responsibility than you'd like to make public, I can respect that too.

 

[Randy Holmes-Farley]

Aside from safety, I do not think it is desirable to dose massively concentrated alk solutions for fear of precipitating calcium carbonate before it disperses.

Sodium hydroxide can be made to 1000 g/L at 25 deg C. Potassium hydroxide can reach 1200+ g/L.

What is the concern with using the recommended potency?

 

[Randy Holmes-Farley]

The recommended potency:

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

Add 283 grams of sodium hydroxide to 1 gallon of fresh water. It will get quite warm. Make sure it doesn't soften your container. This solution will contain about 1,900 meq/L of alkalinity (5,300 dKH). BE CAREFUL WITH THIS SOLUTION: IT HAS A pH ABOVE 14. Do not get it in your eyes or on your skin.

 

[Lycosa]

The recommended potency:

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

Add 283 grams of sodium hydroxide to 1 gallon of fresh water. It will get quite warm. Make sure it doesn't soften your container. This solution will contain about 1,900 meq/L of alkalinity (5,300 dKH). BE CAREFUL WITH THIS SOLUTION: IT HAS A pH ABOVE 14. Do not get it in your eyes or on your skin.

Thank you very much for taking the time to answer. It is very much appreciated! I have a magnetic stirrer and borosilicate glass so I should be fine with being able to handle the heat of the reaction. I do have goggles and gloves as well and will certainly wear them. I'll probably mix up smaller batches and start with small doses just to make sure the tank stays happy. I have a pH controller for monitoring and killing the dose if my pH gets too high.

 

[Randy Holmes-Farley]

Thank you very much for taking the time to answer. It is very much appreciated! I have a magnetic stirrer and borosilicate glass so I should be fine with being able to handle the heat of the reaction. I do have goggles and gloves as well and will certainly wear them. I'll probably mix up smaller batches and start with small doses just to make sure the tank stays happy. I have a pH controller for monitoring and killing the dose if my pH gets too high.

Why do you want to use such a concentrated solution?

 

[Lycosa]

Why do you want to use such a concentrated solution?

I wasn't necessarily wanting that concentrated of a solution. I wanted mainly to know what the alkalinity would be at saturation so I could make a much more dilute solution. I wanted to extrapolate whatever the values were so I could make a solution that would raise my alk 1dkh, for example, without raising calcium. I thought if my salinity was a tad low, I could use Sodium Hydroxide to raise that a bit while also maintaining alkalinity. Same with Potassium Hydroxide. I thought once in a while I'd use that as well if both my salinity and calcium were within a good range. I really didn't want to work with extremely concentrated and dangerous solutions, rather just have a place I could start to get the numbers I was looking for. I also wanted to see how using a sodium or potassium hydroxide solution that would raise my dkh by 1 would affect my pH as compared to Calcium Hydroxide. Just a little test I wanted to work out myself, but without knowing how to titrate alkalinity or having the precise gear, I was hoping to get a alkalinity concentration in g/L that I could use to dilute to get to those numbers I felt comfortable working with. Hopefully that makes sense. I does in my mind. lol

 

[Randy Holmes-Farley]

FWIW, the effect on pH of 1 dKH worth of hydroxide is independent of the cation, whether sodium, calcium, or potassium.

I think using saturation to set concentration is going to be far more challenging than just weighing or volume measuring the dry sodium hydroxide.

 

[Lycosa]

FWIW, the effect on pH of 1 dKH worth of hydroxide is independent of the cation, whether sodium, calcium, or potassium.

I think using saturation to set concentration is going to be far more challenging than just weighing or volume measuring the dry sodium hydroxide.

If I could bug you for one more question... Is the formula 283g = 1900 meq/L linear? Will then 141.5g = 950 meq/L, etc? Thanks

 

[Randy Holmes-Farley]

If I could bug you for one more question... Is the formula 283g = 1900 meq/L linear? Will then 141.5g = 950 meq/L, etc? Thanks

Yes, as long as you dissolve them all in 1 gallon.