Adding Soda Ash

[apellegrino8]

Soda ash is a big hammer when it comes to adding alkalinity (and raising pH). High TA, higher CH, etc can cause clouding.

Best to not use Soda ash. Better is to use baking soda to raise TA (if necessary) and aeration to raise pH.

I tried aeration for a week and got nothing.
Had my jets facing up, if I had to add water I use my old flosser head for cartridge cleaning and made a ton or air bubbles.

no luck, that’s why I went to soda ash. App said to use 5 pounds. I put in about 4,

 

[mknauss]

Aeration will not work if you are using trichlor. You are adding acid all the time. Use Borax instead if necessary.

 

[apellegrino8]

Aeration will not work if you are using trichlor. You are adding acid all the time. Use Borax instead if necessary.

Borax instead of triclor? I e never used it before, what would the BOR do/mean going forward?

 

[CraigChing]

Borax instead of triclor? I e never used it before, what would the BOR do/mean going forward?

Not instead of trichlor, but because you are using trichlor. Marty was suggesting its use to help keep your pH in check due to it crashing because of using trichlor.

 

[CraigChing]

Because @jseyfert3 started it, here’s my stash of empty liquid chlorine bottles

It’s not too bad yet! I think there may be a couple of acid jugs in the mix as well.

 

[JamesW]

In my opinion, I would never use soda ash.

As long as the TA is correct, the pH will be fine.

If the PH is going too low, the TA is too low.

In my opinion, baking soda always works.

 

[apellegrino8]

In my opinion, I would never use soda ash.

As long as the TA is correct, the pH will be fine.

If the PH is going too low, the TA is too low.

In my opinion, baking soda always works.

See this is where I get lost with the TA and PH….if I am reading the baking soda bag right.

if PH and TA is low add baking soda
If TA is where it should be or it high it calls for soda ash and not baking soda

 

[JamesW]

My experience is that the right TA creates the right pH.

If the pH is too low, the TA is too low.

If the pH is dropping too low, raise the TA until the pH stops dropping and is stable.

 

[JamesW]

50 lbs of trichlor in a 25,000 gallon pool will:

Raise fc by 219 ppm
Raise CYA by 133 ppm
Raise salt by 179 ppm
Lower TA by 154 ppm

To offset the acidity of tabs, you have to add about 1.1 lbs of baking soda per pound of trichlor.

For example, if you use 7 tabs, add 3.5 lbs of baking soda and the TA and pH should remain about the same.

The TA will begin to shift from bicarbonate to cyanurate alkalinity as the CYA level rises, so you have to watch the CYA levels to make sure that they don't get away from you.

For example, if the TA is 100 and the pH is 7.6 and you add 50 lb of trichlor and 55 lb of baking soda, the TA will remain at 100, but the carbonate alkalinity will have been reduced by about 44 ppm to 56 ppm.

So, to keep the carbonate alkalinity at 100, you would need to add an additional 16 lb of baking soda or a total of 71 lbs of baking soda per 50 lb. of trichlor.

That's 1.42 lb of baking soda per lb of trichlor.

Depending on what the pH does, you will need between about 1.1 and 1.4 lb of baking soda per lb of trichlor.

 

[JamesW]

2C₃CL₃N₃O₃ + 6H₂O --> 2C₃H₂N₃O₃^- + 6Cl^- + 8H⁺ + 3O₂

Trichlor + water --> Cyanurate + chloride + hydrogen ions (aka acid) + oxygen gas.

8HCO₃^- + 8H⁺+ --> 8H₂CO₃ --> 8H₂O + 8CO₂

Bicarbonate + hydrogen ions --> carbonic acid --> water + carbon dioxide.

The carbon dioxide will offgass due to aeration or just naturally without aeration.

 

[CraigChing]

This is why I don’t like trichlor tabs, pool maintenance gets much more complicated compared to liquid chlorine and muriatic acid for daily maintenance.

 

[JamesW]

Trichlor is 232.41 grams per mole.

Sodium bicarbonate is 84 grams per mole.

It takes 3 moles of sodium bicarbonate to offset the acidity of trichlor.

It takes 252 grams of sodium bicarbonate to offset 232.41 grams of trichlor.

252 ÷ 232 = 1.1.

But, that's for the total alkalinity.

If you look at the pH, it takes 4 moles of sodium bicarbonate per mole of trichlor.

84 x 4 ÷ 232.41 = 1.45.

 

[JamesW]

100C3CL3N3O3 + 300H2O --> 16C3H3N3O3 + 84C3H2N3O3 + 300Cl + 384H + 150O2

At a pH of 7.6, 84% will be cyanurate and 16% will be cyanuric acid.

So, 3.84 moles of sodium bicarbonate per mole of trichlor.

84 x 3.84 ÷ 232.41 = 1.39.

So, 1.39 lb. sodium bicarbonate per 1 lb of trichlor will be pH and carbonate alkalinity neutral.

The total alkalinity will increase by 1/3 of the CYA increase.

If the CYA increases by 3 ppm, the TA increases by 1 ppm.

For example, if you know that you will use 5 lbs of trichlor over the next two weeks, you can add about 6 to 7 lbs of baking soda to offset the acidity of the trichlor so that the pH and TA are the same after using the trichlor.

 

[apellegrino8]

I got some good feedback and advice on another post I made about sodas ash.

I’m not sure if my signature shows (posting on my phone)….but, I heard Borax is a good alternative to Soda Ash.
When I plug into the “effects of adding” it shows that it will raise a BOR reading in the pool.
I use tabs for chlorine, and cal hypo 73 for shock. Switching to a SWG is not in the plans.
My question is…what effects will I have if switching o we to Borax, and out of my chemicals what should I drop…soda ash?

does it make sense to do the change now, or is it worth it to use up what I have this season and change over leading into next season when I open it.

 

[mknauss]

My question is…what effects will I have if switching o we to Borax, and out of my chemicals what should I drop…soda ash?

Baking Soda = big TA change, small pH change
Borax = Big pH change, small TA change
Washing Soda = big pH change, big TA change. Probably more TA change than you want.

So, borax does add borates. You would have to add more than 50 lbs of borax before the level of borates rises to a level that will effect how your acid additions effect your pH. You can get a borates test kit if you wish to keep track of your borates.

 

[apellegrino8]

My experience is that the right TA creates the right pH.

If the pH is too low, the TA is too low.

If the pH is dropping too low, raise the TA until the pH stops dropping and is stable.

But if the numbers are where they should be why the change?

50 lbs of trichlor in a 25,000 gallon pool will:

Raise fc by 219 ppm
Raise CYA by 133 ppm
Raise salt by 179 ppm
Lower TA by 154 ppm

To offset the acidity of tabs, you have to add about 1.15 lbs of baking soda per pound of trichlor.

For example, if you use 7 tabs, add 3.5 lbs of baking soda and the TA and pH should remain about the same.

The TA will begin to shift from bicarbonate to cyanurate alkalinity as the CYA level rises, so you have to watch the CYA levels to make sure that they don't get away from you.

Baking Soda = big TA change, small pH change
Borax = Big pH change, small TA change
Washing Soda = big pH change, big TA change. Probably more TA change than you want.

So, borax does add borates. You would have to add more than 50 lbs of borax before the level of borates rises to a level that will effect how your acid additions effect your pH. You can get a borates test kit if you wish to keep track of your borates.

Sums it up easy. Thanks

Do borates go away on their own? Or get diluted/go away when refilling or vacuuming?

This is a new item for me

 

[apellegrino8]

Is this what I am looking for?

 

[mknauss]

Do borates go away on their own? Or get diluted/go away when refilling or vacuuming?

They only go away when you drain or vac to waste, etc.

Is this what I am looking for?

Yes.

 

[JamesW]

But if the numbers are where they should be why the change?

There is no absolute hard number for TA.

The correct TA is where the pH is stable.

In any case, baking soda or Borax will work for you, whichever you prefer.

 

[jseyfert3]

But if the numbers are where they should be why the change?

The TFP recommended TA levels of 50-90 are based on the assumption of adding liquid chlorine or a SWCG as the primary chlorine source, since tablets are not generally recommended for the primary chlorine source here as previously discussed. When using liquid chlorine or a SWCG, a TA in this range will typically give a fairly steady pH, or slowly climbing, the latter of which can be easily adjusted by occasional acid additions which work to making the pH even more stable over time.

If you use trichlor as your primary source of chlorine, since that is essentially like adding acid continuously it results in a pH drop when your TA is at these levels. So you need to run a higher TA than what is listed as the TFP recommended levels to have a steady pH, since you’re not chlorinating per the two primary methods TFP recommends. Make sense?