DIY 2 part mixing

[USMA36]

long winded, but hopefully an easy question. I started using Randy’s sodium hydroxide recipe for alk. Wow! What a difference. My normally low ph jumped and now I max out at 8.6. My 2 part consumption more than doubled. I’m dosing 350 ml a day of each and I still can’t get alk to 8.5 and calcium 420. I’m around 7.3 and 400 calcium measured by trident. I think I’m probably losing a fair bit of 2 part to precipitation. id Like to back my pH down to a high of 8.3. As I understand it I can use soda ash recipe mixed with the sodium hydroxide recipe. Can the same be done using sodium bicarbonate? Or does that throw the math off since it doesn’t contain the same alk level of the sodium hydroxide. my Dosing container is 5 gallons. I plan on 3 gallons of sodium hydroxide and 2 of either carbonate or bicarbonate. Lastly Amazon sells soda ash for pools. Would this be safe to use or should I stick with brs soda ash or diy. Pool soda ash on Amazon.

 

[Randy Holmes-Farley Verified Community Expert]

A 1:1 molar mix of bicarbonate and hydroxide gives the exact carbonate recipe, so there’s little reason to make such a mix.

 

[USMA36]

A 1:1 molar mix of bicarbonate and hydroxide gives the exact carbonate recipe, so there’s little reason to make such a mix.

Would the ph effect of the sodium hydroxide be reduced if I did 80% sodium hydroxide and 20% sodium bicarbonate? Sodium bicarbonate alone wasn’t enough to keep ph where I wanted it. Your Sodium hydroxide is I just want to reduce how well it boosts pH.

 

[Randy Holmes-Farley Verified Community Expert]

Would the ph effect of the sodium hydroxide be reduced if I did 80% sodium hydroxide and 20% sodium bicarbonate? Sodium bicarbonate alone wasn’t enough to keep ph where I wanted it. Your Sodium hydroxide is I just want to reduce how well it boosts pH.

That is ok. It’s like a mix of 60% hydroxide and 40% carbonate.

One hydroxide plus one bicarbonate is identical to two carbonates

 

[USMA36]

That is ok. It’s like a mix of 60% hydroxide and 40% carbonate.

One hydroxide plus one bicarbonate is identical to two carbonates

Thank you!

 

[KTTX]

Can these two be mixed together in same container? 70% sodium hydroxide and 30% sodium bicarbonate...I have same issue with Ph too high.

 

[USMA36]

Yes. I’m doing that with sodium carbonate. (Baked baking soda) you’ll be better off with carbonate. The bicarbonate pretty much cancelled out the pH gains from the hydroxide. I’m using 2 gallons carbonate 3 gallons hydroxide. I’m probably going to switch to 4:1 hydroxide the 3:2 reduced my ph a little too much.

 

[Randy Holmes-Farley Verified Community Expert]

Can these two be mixed together in same container? 70% sodium hydroxide and 30% sodium bicarbonate...I have same issue with Ph too high.

Yes. It will have a somewhat bigger pH effect than sodium carbonate.

 

[KTTX]

Yes. I’m doing that with sodium carbonate. (Baked baking soda) you’ll be better off with carbonate. The bicarbonate pretty much cancelled out the pH gains from the hydroxide. I’m using 2 gallons carbonate 3 gallons hydroxide. I’m probably going to switch to 4:1 hydroxide the 3:2 reduced my ph a little too much.

So out of 283grams your are going to do 212

Yes. It will have a somewhat bigger pH effect than sodium carbonate.

The 283 grams od sodium hydroxide gives a pH over 14+. This 4 to 1 (sodium hydroxide to carbonate) mix will reduce that 14+ to hopefully 6 or so.

 

[Randy Holmes-Farley Verified Community Expert]

The 283 grams od sodium hydroxide gives a pH over 14+. This 4 to 1 (sodium hydroxide to carbonate) mix will reduce that 14+ to hopefully 6 or so.

What? pH of the dosing solution is not a useful gauge of the pH effect when added to seawater. Sodium bicarbonate alone has a pH over 8.5, but when added to seawater at pH 8.2, it lowers pH.

 

[KTTX]

What? pH of the dosing solution is not a useful gauge of the pH effect when added to seawater. Sodium bicarbonate alone has a pH over 8.5, but when added to seawater at pH 8.2, it lowers pH.

Yea I understand that...but the sodium hydroxide solution is raising my pH 0.4+ more than I want it to. So trying to change the solution to not raise the pH so high.

 

[Randy Holmes-Farley Verified Community Expert]

Yea I understand that...but the sodium hydroxide solution is raising my pH 0.4+ more than I want it to. So trying to change the solution to not raise the pH so high.

Sure.

What does the normal sodium carbonate recipe do?

 

[KTTX]

Sure.

What does the normal sodium carbonate recipe do?

If I recall my pH was too low hovering around 7.5 to 7.8...so I was very glad that I found the DIY solution you helped everyone with.

 

[Randy Holmes-Farley Verified Community Expert]

If I recall my pH was too low hovering around 7.5 to 7.8...so I was very glad that I found the DIY solution you helped everyone with.

A mixture is certainly fine. I’m just surprised the effect is so low with carbonate and too high with hydroxide.

 

[USMA36]

So out of 283grams your are going to do 212

The 283 grams od sodium hydroxide gives a pH over 14+. This 4 to 1 (sodium hydroxide to carbonate) mix will reduce that 14+ to hopefully 6 or so.

No I’m doing 4 gallons of the sodium hydroxide solution to 1 gallon of Randy’s carbonate recipe. From my limited understanding they can be mixed and it doesn’t mess up dosing numbers since they both increase the dkh by the same amount.