Safely and Easily Mixing Sodium Hydroxide: A Step-by-Step Guide

[Miami Reef]

Sodium hydroxide raises pH equally to kalkwasser when increasing equal units of alkalinity. Sodium hydroxide is caustic. Please read this for your safety:

Sodium Hydroxide | Medical Management Guidelines | Toxic Substance Portal | ATSDR

wwwn.cdc.gov

Many people enjoy using Sodium hydroxide because you can make it more concentrated than kalkwasser. This tutorial uses the standard DIY 2 and 3 Part concentration.

BE CAREFUL WITH THIS SOLUTION: IT HAS A pH ABOVE 14. Avoid contact with eyes and skin.

If your hands or skin ever feel slippery during this process, wash them immediately. This will happen when sodium hydroxide comes in contact with skin.


Use proper PPE, including gloves, goggles, and a lab coat, to protect yourself from spills.


This method is highly refined, perfected after over two years of mixing and making batches.


Items Needed:

• Food-grade sodium hydroxide
• Plastic gallon jug (polypropylene or polyethylene, such as HDPE, which is often used for vinegar bottles)
• Funnel
• Glass beaker or cup
• Gram scale
• Refrigerated RO/DI water
• Gloves and other protective gear
• Paper towels and a nearby sink for accidental spills
• Optional: Glass rod

Step 1: Fill the plastic jug about 3/4 full with RO/DI water and refrigerate overnight until cold.

You can also use ice or partially frozen RO/DI. I find partially frozen water still very cold, even after adding the hydroxide, so it’s probably a bit overkill, but there’s no harm in doing so: the cold won’t ruin the sodium hydroxide.


Step 2: Weigh out 283g of sodium hydroxide per gallon in the glass container.


Step 3: Using the funnel, carefully pour the dry sodium hydroxide into the plastic jug.


Step 4: Cap the jug, hold the cap firmly, and shake vigorously to dissolve the sodium hydroxide and disperse the heat. Cold water prevents the jug from becoming too hot to handle or potentially melting, as the exothermic reaction generates significant heat. This step eliminates the need for magnetic stirrers and transferring multiple small batches.


Step 5: If any sodium hydroxide remains in the glass beaker/cup, add some water and gently swirl or stir with a glass rod to dissolve. Pour the dissolved hydroxide into the solution.


Step 6: Top off the jug with RO/DI water and gently invert a few times.



Here are some photos of the process:

283 grams of NaOH in a beaker beside a refrigerated jug of RO/DI water.

This funnel is extremely useful for this project. I like the large size of it for easy and quick decanting.


For questions, concerns, or feedback, feel free to reach out here.



Happy Mixing!

 

[Formulator]

Thanks for the nice write up. I just switched to NaOH in my 2-part and the first time I mixed this up I did it completely wrong, despite being a trained chemist. Thought the heat was going to melt my bottle!

 

[Miami Reef]

Thank you so much. I’m glad it was useful.

 

[geko522]

Sodium hydroxide raises pH equally to kalkwasser when increasing equal units of alkalinity.

Many people enjoy using Sodium hydroxide because you can make it more concentrated than kalkwasser. This tutorial uses the standard DIY 2 and 3 Part concentration.

BE CAREFUL WITH THIS SOLUTION: IT HAS A pH ABOVE 14. Avoid contact with eyes and skin.

If your hands or skin ever feel slippery during this process, wash them immediately. This will happen when sodium hydroxide comes in contact with skin.


Use proper PPE, including gloves, goggles, and a lab coat, to protect yourself from spills.


This method is highly refined, perfected after over two years of mixing and making batches.


Items Needed:

• Food-grade sodium hydroxide
• Plastic gallon jug (polypropylene or polyethylene, such as HDPE, which is often used for vinegar bottles)
• Funnel
• Glass beaker or cup
• Gram scale
• Refrigerated RO/DI water
• Gloves and other protective gear
• Paper towels and a nearby sink for accidental spills
• Optional: Glass rod

Step 1: Fill the plastic jug about 3/4 full with RO/DI water and refrigerate overnight until cold.

You can also use ice or partially frozen RO/DI. I find partially frozen water still very cold, even after adding the hydroxide, so it’s probably a bit overkill, but there’s no harm in doing so: the cold won’t ruin the sodium hydroxide.


Step 2: Weigh out 283g of sodium hydroxide per gallon in the glass container.


Step 3: Using the funnel, carefully pour the dry sodium hydroxide into the plastic jug.


Step 4: Cap the jug, hold the cap firmly, and shake vigorously to dissolve the sodium hydroxide and disperse the heat. Cold water prevents the jug from becoming too hot to handle or potentially melting, as the exothermic reaction generates significant heat. This step eliminates the need for magnetic stirrers and transferring multiple small batches.


Step 5: If any sodium hydroxide remains in the glass beaker/cup, add some water and gently swirl or stir with a glass rod to dissolve. Pour the dissolved hydroxide into the solution.


Step 6: Top off the jug with RO/DI water and gently invert a few times.



Here are some photos of the process:

283 grams of NaOH in a beaker beside a refrigerated jug of RO/DI water.

This funnel is extremely useful for this project. I like the large size of it for easy and quick decanting.


For questions, concerns, or feedback, feel free to reach out here.

Happy Mixing!

Thanks for the info. I was wondering about a very basic guidelines for dosing this? Something like x amount of ml to x amount gallons to dose. I'd like to raise my pH and currently using kalkwasser and co2 scrubber and can only get it at 7.9 day time and 7.8 at night.

 

[Swede's Reef]

Sodium hydroxide raises pH equally to kalkwasser when increasing equal units of alkalinity.

Many people enjoy using Sodium hydroxide because you can make it more concentrated than kalkwasser. This tutorial uses the standard DIY 2 and 3 Part concentration.

BE CAREFUL WITH THIS SOLUTION: IT HAS A pH ABOVE 14. Avoid contact with eyes and skin.

If your hands or skin ever feel slippery during this process, wash them immediately. This will happen when sodium hydroxide comes in contact with skin.


Use proper PPE, including gloves, goggles, and a lab coat, to protect yourself from spills.


This method is highly refined, perfected after over two years of mixing and making batches.


Items Needed:

• Food-grade sodium hydroxide
• Plastic gallon jug (polypropylene or polyethylene, such as HDPE, which is often used for vinegar bottles)
• Funnel
• Glass beaker or cup
• Gram scale
• Refrigerated RO/DI water
• Gloves and other protective gear
• Paper towels and a nearby sink for accidental spills
• Optional: Glass rod

Step 1: Fill the plastic jug about 3/4 full with RO/DI water and refrigerate overnight until cold.

You can also use ice or partially frozen RO/DI. I find partially frozen water still very cold, even after adding the hydroxide, so it’s probably a bit overkill, but there’s no harm in doing so: the cold won’t ruin the sodium hydroxide.


Step 2: Weigh out 283g of sodium hydroxide per gallon in the glass container.


Step 3: Using the funnel, carefully pour the dry sodium hydroxide into the plastic jug.


Step 4: Cap the jug, hold the cap firmly, and shake vigorously to dissolve the sodium hydroxide and disperse the heat. Cold water prevents the jug from becoming too hot to handle or potentially melting, as the exothermic reaction generates significant heat. This step eliminates the need for magnetic stirrers and transferring multiple small batches.


Step 5: If any sodium hydroxide remains in the glass beaker/cup, add some water and gently swirl or stir with a glass rod to dissolve. Pour the dissolved hydroxide into the solution.


Step 6: Top off the jug with RO/DI water and gently invert a few times.



Here are some photos of the process:

283 grams of NaOH in a beaker beside a refrigerated jug of RO/DI water.

This funnel is extremely useful for this project. I like the large size of it for easy and quick decanting.


For questions, concerns, or feedback, feel free to reach out here.

Happy Mixing!

Very timely! Thank you for this. Very helpful...

 

[Miami Reef]

Thanks for the info. I was wondering about a very basic guidelines for dosing this? Something like x amount of ml to x amount gallons to dose. I'd like to raise my pH and currently using kalkwasser and co2 scrubber and can only get it at 7.9 day time and 7.8 at night.

You should ideally use it to increase alkalinity. The recipe noted above has the exact alkalinity concentration as the standard sodium carbonate (soda ash) in the 2 part.

Use this calculator and select “liquid soda ash”

Alkalinity Supplement Calculator - Bulk Reef Supply

Bulk Reef Supply - Saltwater Aquarium Supplies for Reef Tanks

www.bulkreefsupply.com

 

[Miami Reef]

Very timely! Thank you for this. Very helpful...

Thank you very much!

 

[geko522]

You should ideally use it to increase alkalinity. The recipe noted above has the exact alkalinity concentration as the standard sodium carbonate (soda ash) in the 2 part.

Use this calculator and select “liquid soda ash”

Alkalinity Supplement Calculator - Bulk Reef Supply

Bulk Reef Supply - Saltwater Aquarium Supplies for Reef Tanks

www.bulkreefsupply.com

Would I also follow the recipe they suggested if I'm using sodium hydroxide? I'm sorry, I'm really new to this and I don't know if liquid soda ash is the same as sodium hydroxide. Thanks for helping me!

 

[Miami Reef]

Would I also follow the recipe they suggested if I'm using sodium hydroxide? I'm sorry, I'm really new to this and I don't know if liquid soda ash is the same as sodium hydroxide. Thanks for helping me!

This is the full recipe when using sodium hydroxide.

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

 

[Slocke]

Sodium hydroxide raises pH equally to kalkwasser when increasing equal units of alkalinity.

Many people enjoy using Sodium hydroxide because you can make it more concentrated than kalkwasser. This tutorial uses the standard DIY 2 and 3 Part concentration.

BE CAREFUL WITH THIS SOLUTION: IT HAS A pH ABOVE 14. Avoid contact with eyes and skin.

If your hands or skin ever feel slippery during this process, wash them immediately. This will happen when sodium hydroxide comes in contact with skin.


Use proper PPE, including gloves, goggles, and a lab coat, to protect yourself from spills.


This method is highly refined, perfected after over two years of mixing and making batches.


Items Needed:

• Food-grade sodium hydroxide
• Plastic gallon jug (polypropylene or polyethylene, such as HDPE, which is often used for vinegar bottles)
• Funnel
• Glass beaker or cup
• Gram scale
• Refrigerated RO/DI water
• Gloves and other protective gear
• Paper towels and a nearby sink for accidental spills
• Optional: Glass rod

Step 1: Fill the plastic jug about 3/4 full with RO/DI water and refrigerate overnight until cold.

You can also use ice or partially frozen RO/DI. I find partially frozen water still very cold, even after adding the hydroxide, so it’s probably a bit overkill, but there’s no harm in doing so: the cold won’t ruin the sodium hydroxide.


Step 2: Weigh out 283g of sodium hydroxide per gallon in the glass container.


Step 3: Using the funnel, carefully pour the dry sodium hydroxide into the plastic jug.


Step 4: Cap the jug, hold the cap firmly, and shake vigorously to dissolve the sodium hydroxide and disperse the heat. Cold water prevents the jug from becoming too hot to handle or potentially melting, as the exothermic reaction generates significant heat. This step eliminates the need for magnetic stirrers and transferring multiple small batches.


Step 5: If any sodium hydroxide remains in the glass beaker/cup, add some water and gently swirl or stir with a glass rod to dissolve. Pour the dissolved hydroxide into the solution.


Step 6: Top off the jug with RO/DI water and gently invert a few times.



Here are some photos of the process:

283 grams of NaOH in a beaker beside a refrigerated jug of RO/DI water.

This funnel is extremely useful for this project. I like the large size of it for easy and quick decanting.


For questions, concerns, or feedback, feel free to reach out here.

Happy Mixing!

I would suggest for extra caution, a full face shield and two sets of gloves with the inside set taped over the sleeves of an impermeable lab coat or tyvek suit. If you feel a soapiness on your skin immediately wash your skin thoroughly.

Also store in an air tight plastic (not glass) jug

 

[DanyL]

These are good, and cautious instructions - will be very useful for all of us to share and improve our methods with each other.

I use a large lab grade plastic beaker with a handle for the mixing process, fill it about 60% with regular, room temperature RODI and than start to slowly add the NaOH while mixing in between (I used to mix it manually, but switched to a magnetic stirrer later on).

Finally, I flush the container with the remaining NaOH with some RODI water, fill it to the final volume and than using a large funnel to transfer it to a container where I’ll be dosing from.

I understand your concern about the heat, however - I make my concentration 3 times more potent than yours (160g per Liter, or 606.4 grams per gallon), and yes while it does get very hot, using a lab grade container that can handle high temperatures ensures it wouldn’t suddenly melt or deform, and adding the NaOH in smaller portions also slows down the reaction.

I do like your suggestion of using cold RODI water however, and will implement it as well.

The reason why I’ll continue using my own process over shaking a jug however, is that from my experience - you don’t always notice when the cap isn’t fully or correctly screwed on, eventual wear to the threads is inevitable too, and this may lead to a leak or a splash.
With NaOH this can be hazardous, and I think being less erratic around it would be a safer approach.

 

[Miami Reef]

@DanyL

I understand your concern. I used to make sodium hydroxide in batches with a magnetic stirrer in a borosilicate beaker, but the beaker would get super hot, too hot to handle without excessive mixing. I also spilled many times during the transferring process.

Sodium hydroxide is used in drain cleaners and making DIY soap. It’s only harmful when misused.

We should still practice caution, of course.

 

[DanyL]

I understand your concern. I used to make sodium hydroxide in batches with a magnetic stirrer in a borosilicate beaker, but the beaker would get super hot, too hot to handle without excessive mixing. I also spilled many times during the transferring process.

I think I might haven’t been clear in my previous post - I make the whole solution in one batch, but add the NaOH slowly in portions.

The benefit of using a plastic measuring cup, is that it comes with a handle, and weight far less than a large glass beaker - thus making it easier to handle.

These are the measuring cups I use, not all are lab grade though. The bigger one can hold 5 Liters with enough space left on top for safety.

Sodium hydroxide is used in drain cleaners and making DIY soap. It’s only harmful when misused.

I agree, however I think(?) the concentrations we are dealing with here are far more potent than used in the soap industry, and it is a different application than used as a drain clean with possibly more room for mistakes.

Strictly following the generally accepted handling guidelines should be well enough to be safe though.

 

[Dburr1014]

These are good, and cautious instructions - will be very useful for all of us to share and improve our methods with each other.

I use a large lab grade plastic beaker with a handle for the mixing process, fill it about 60% with regular, room temperature RODI and than start to slowly add the NaOH while mixing in between (I used to mix it manually, but switched to a magnetic stirrer later on).

Finally, I flush the container with the remaining NaOH with some RODI water, fill it to the final volume and than using a large funnel to transfer it to a container where I’ll be dosing from.

I understand your concern about the heat, however - I make my concentration 3 times more potent than yours (160g per Liter, or 606.4 grams per gallon), and yes while it does get very hot, using a lab grade container that can handle high temperatures ensures it wouldn’t suddenly melt or deform, and adding the NaOH in smaller portions also slows down the reaction.

I do like your suggestion of using cold RODI water however, and will implement it as well.

The reason why I’ll continue using my own process over shaking a jug however, is that from my experience - you don’t always notice when the cap isn’t fully or correctly screwed on, eventual wear to the threads is inevitable too, and this may lead to a leak or a splash.
With NaOH this can be hazardous, and I think being less erratic around it would be a safer approach.

Yeah, I agree not shaking a closed bottle. The heat will have expansion and mixture will be on the cap. When opening, the air will release and spray the mixture. Much safer to stir in an open container to avoid spray.

 

[geko522]

This is the full recipe when using sodium hydroxide.

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

Thank you