Mixing and storing Lye

[Brett S]

So I’m getting ready to start dosing lye (sodium hydroxide) for alkalinity and to help raise my pH. My dosing container is acrylic, and it’s my understanding that acrylic is fine for lye. However, I was planning to mix and store it in one of the BRS mixing jugs. On the bottom it’s labeled as number 3 plastic, which I believe is polyvinyl chloride. Would that be OK to mix and store the lye in? I’m a bit concerned that it might soften due to the heat generated while I mix it. Would it be better to mix the lye in something else (glass maybe?). After it’s mixed and cooled down can I store it in the PVC jug?

 

[Randy Holmes-Farley]

Some thoughts.

The big thing to avoid is polycarbonate.

I cannot confirm that acrylic is OK.
PVC will not be damaged by high pH, but there is some possibility of PVC leaching tin.

Polyethylene and polypropylene are among the best for high pH solutions.

 

[Brett S]

Some thoughts.

The big thing to avoid is polycarbonate.

I cannot confirm that acrylic is OK.
PVC will not be damaged by high pH, but there is some possibility of PVC leaching tin.

Polyethylene and polypropylene are among the best for high pH solutions.

Thanks for the reply. I found that there’s a lot of good info on lye if you look at the soap making interest groups. It seems like they recommend HDPE as well. Maybe I should rethink my acrylic dosing container and go with something that’s HDPE for that as well.

One last question... does lye create gas or expand when it’s mixed with water? In other words, could I put lye and water in a sealed jug and shake it to mix it or would that build up pressure and be dangerous?

 

[Randy Holmes-Farley]

Thanks for the reply. I found that there’s a lot of good info on lye if you look at the soap making interest groups. It seems like they recommend HDPE as well. Maybe I should rethink my acrylic dosing container and go with something that’s HDPE for that as well.

One last question... does lye create gas or expand when it’s mixed with water? In other words, could I put lye and water in a sealed jug and shake it to mix it or would that build up pressure and be dangerous?

Lye gets hot when it dissolves. Dissolve it in a lot of cool water. No gas is released, unless you boil the water. lol

 

[Brett S]

Lye gets hot when it dissolves. Dissolve it in a lot of cool water. No gas is released, unless you boil the water. lol

Thanks again All my stuff should be arriving tomorrow or Thursday, so if you don’t hear from me after that you can assume that something terrible happened

 

[Randy Holmes-Farley]

Thanks again All my stuff should be arriving tomorrow or Thursday, so if you don’t hear from me after that you can assume that something terrible happened

OK, lots of luck! lol

 

[dazoc]

So after mixing, initial heat up and cool down I can long term store in a milk jug, says they are made from polyethylene and polyester

 

[Brett S]

I just ordered this on amazon...



I’m planning to mix and store in that container. A milk jug might work, but it’s pretty thin plastic. In my research today a lot of sites recommended against thin plastic because it could be easily damaged if it is accidentally dropped or punctured and spilled lye could be a lot more dangerous than spilled milk. I figure for $8 I might as well get something that will hopefully be a little tougher.

 

[Randy Holmes-Farley]

I just ordered this on amazon...



I’m planning to mix and store in that container. A milk jug might work, but it’s pretty thin plastic. In my research today a lot of sites recommended against thin plastic because it could be easily damaged if it is accidentally dropped or punctured and spilled lye could be a lot more dangerous than spilled milk. I figure for $8 I might as well get something that will hopefully be a little tougher.

That's a good choice.

 

[Randy Holmes-Farley]

So after mixing, initial heat up and cool down I can long term store in a milk jug, says they are made from polyethylene and polyester

A polyester may not hold up long term. The "ester' will slowly break apart at high pH.

 

[Greg Hiller]

If you dilute your NaOH it will be less problematic for the container. For "inertness" for the vast majority of chemicals (save HF!!) I usually like glass. I'd also suggest you minimize the exposure of your NaOH to air as in time it will pull CO2 out of the air and you might end up with a bit of residue in your bottle. Not a problem, just don't be surprised. Also in the FWIW category, I'd be very careful hooking a large bottle of any strong chemical to your reef tank. Bad things can happen when timers fail, pump tubing breaks or siphons start unexpectedly.

 

[Randy Holmes-Farley]

If you dilute your NaOH it will be less problematic for the container. For "inertness" for the vast majority of chemicals (save HF!!) I usually like glass. I'd also suggest you minimize the exposure of your NaOH to air as in time it will pull CO2 out of the air and you might end up with a bit of residue in your bottle. Not a problem, just don't be surprised. Also in the FWIW category, I'd be very careful hooking a large bottle of any strong chemical to your reef tank. Bad things can happen when timers fail, pump tubing breaks or siphons start unexpectedly.

Good point, and good to see you here, Greg!

To that end, I drew vinegar directly from a 1 gallon bottle by having the drip end higher than the bottle (and not submerged) so that siphoning could never happen.

 

[Brett S]

The bottle and my lye arrived today and I have mixed my first batch with no issues. It definitely generated a bit of heat, but nothing too crazy.

Also, I wasn’t expecting it, but the bottle that I linked above came with a child proof cap. I don’t have small children around my house, but it’s probably still a good safety precaution.

 

[Randy Holmes-Farley]

Also, I wasn’t expecting it, but the bottle that I linked above came with a child proof cap. I don’t have small children around my house, but it’s probably still a good safety precaution.

Definitely.