Order of chemical additions...

[Henrys514]

After some much needed rain this weekend, I need to raise both my TA and Calcium. I'm going away this weekend, so I need to shock the pool Thursday before I go. That leaves me with tomorrow and Wed. to add chemcials. My question is, which chemicals should I add first? If I recall, the Calcium stuff you have to add on a day all by itself. Pool is 12,000gal exposed aggregate surface. Here are some numbers from my testkit:

CYA-~45ppm
TC-6ppm
pH-7.5
TA-50
CH-180

Thanks!

[CarlD]

Calcium first. You can use Cal-Hypo to chlorinate--it will do both. You are close on CH to the 200 minimum.

Cal-hypo makes pH rise. The will raise T/A with it, but probably not enough.

But for your pool the CH is more important than the TA, so do that first, get it good, then add baking soda to raise TA.

[Henrys514]

Thanks for the response Carl. I will do the Calcium first...probably tonight. I have some Calcium Hardness increaser (from pool store) leftover that I was going to use to raise CH. I can't think of what chemical exactly that it is...will that stuff work too? I'd like to get rid of it if I can...I can use the calcium hypo next time (i didn't even know they made that). Should I shoot for 250-300ppm do you think?

Then I can do TA tomorrow evening. Then I can adjust the pH as needed (probably add some acid) Thursday morning. Then shock with bleach before I leave Thursday. Hopefully, my water will still look pretty when I get home Sunday night. Thanks!

[waterbear]

Thanks for the response Carl. I will do the Calcium first...probably tonight. I have some Calcium Hardness increaser (from pool store) leftover that I was going to use to raise CH. I can't think of what chemical exactly that it is
It's calcium chloride and it's what you should use if you need to raise the calcium a lot. Cal hypo will not raise your calcium that quickly.
...will that stuff work too? I'd like to get rid of it if I can...I can use the calcium hypo next time (i didn't even know they made that). Should I shoot for 250-300ppm do you think?

Then I can do TA tomorrow evening.
When you add the baking soda add a small amount at a time dissolved in water and broadast it in the pool. If you see any local cloudiness develop you are adding too much at once and you need to add less at a time.
Then I can adjust the pH as needed (probably add some acid) Thursday morning. Then shock with bleach before I leave Thursday. Hopefully, my water will still look pretty when I get home Sunday night. Thanks!

Sounds like a plan. It's generally a good idea to wait about 24 hours after raising TA so the pool can stabilizer. There is a bit of chemistry going on in the water when you raise TA with baking soda but you should be ok.

[duraleigh]

Evan,

When you add the baking soda add a small amount at a time dissolved in water and broadast it in the pool. If you see any local cloudiness develop you are adding too much at once and you need to add less at a time.

I have plopped it directly into the skimmer without dissolving. Is there a distinct advantage in dissolving and broadcasting?

[waterbear]

Depends on where your calcium is. If it's high it can cause clouding of the water. I am just being cautious since he is adding calcium and baking soda in a short period of time.

[Henrys514]

Sounds like a plan. It's generally a good idea to wait about 24 hours after raising TA so the pool can stabilizer. There is a bit of chemistry going on in the water when you raise TA with baking soda but you should be ok.

Thanks waterbear. I don't normally like to add all the chemicals in such rapid succession, but my hands are tied in this case if I want it taken care of before I leave. I'm probably going to have to add acid Thursday morning, and then bleach shortly after that unless I can get someone to come and do it for me. My normal schedule is acid AM, bleach PM.

[CarlD]

If you have calcium and don't have cal-hypo, you don't need to buy cal-hypo. Just use what you have for the calcium and use whatever chlorinator chem you have for the chlorine.

If you had neither the Cal-Hypo is a good one-step solution, but no need to buy it otherwise.