Adding sodium bicarbonate

[m100psi]

Hi,

I've had my pool about 6 months now, and today the TA measured 40 ppm (it had been around 60-70 previously). To be conservative and not overshoot, I figured I'd bring it up to 70 ppm, but that's still 7 lb of sodium bicarbonate according to the container. What is the best way to add it? Do I need to go fill up 10 socks like adding CYA, or does it dissolve easily enough I can just sprinkle it in and no big deal if some settles to the bottom?

Just curious, the drop in TA occurred at the same time I switched from trichlor tablets to liquid chlorine. Are the two related?

Thanks,
Matt

 

[mknauss]

I would not add any sodium bicarb just yet.

If all you did was switch from trichlor to liquid chlorine, that should not have effected your TA. In fact, the trichlor would have been pushing the TA down as it is acidic.

Check your trichlor tablets. Do they have bicarb in them?

 

[m100psi]

No bicarb as far as I can see, though I don't know what the "other ingredients" are.

Why the recommendation to avoid adding if I'm below the recommended value? Or are you just suggesting to measure again and double-check?

I was also going to pick up some calcium chloride as CH has been consistently testing 130-140 ppm. Should I hold off on that also?

Thanks,
Matt

 

[mknauss]

That Other is something. No additive tabs are 99% plus trichlor. I would bet they have bicarb in them. Some tablet manufacturers do that to compensate for the acidic nature of the tablets.

I assume you are doing your own testing? Please add what test kit you use to your signature.

If you are confident in the testing, add enough bicarb to get to 70 ppm. Just sprinkle it in the pool. Break it up in a few batches and brush to be sure it is mixed in.

Same with the calcium carbonate. What is the CH of your fill water? Be careful on adding calcium if your fill water is high in calcium. It will build up quick enough due to evaporation.

 

[m100psi]

I see. I guess the decrease makes sense moving away from the tablets, then.

I will test TA again, and add as you described if it needs it. I use a k-2006.

I've done the testing since the beginning, and CH has always measured ~130 ppm. I can measure the fill water beforehand. What is your method for using the CH of the fill water to determine your measured pool water target?

Thanks for the help, and the recommendation of the app in your signature. I didn't know about it and it's pretty sweet.

Matt

 

[mknauss]

Your pool CH will increase over time as you add fill water due to evaporation.