Need Advice On Chemicals

[aGrandma]

I tested my own water with the Taylor k-2006 kit. Here are my results:

FC = 8

CC=0

pH = 7.8

Alkalinity = 40

Calcium = 220

CYA = 50

I took a sample to Leslies and this is what they told me:

Free Chlorine = 4

Total Available Chlorine = 4

Calcium hardness = 130

CYA = 25

Total Alkalinity = 50

pH 8.0

Acid Demand 2

copper 0

iron 0

phosphates 200

Their results are different from mine - and I trust my results more. But they are telling me to buy "alkalinity up" (10.5 lbs of it) from them do that first, then add 25 lbs of "hardness plus" to increase calcium hardness. Then I should add "phos free" to get rid of the phosphates. I asked them if I could use baking soda or soda ash and they said no, I have to use "alkalinity up".

Advice? (Thank you!!)

[chem geek]

You can absolutely use baking soda instead of Alkalinity Up since both are identical sodium bicarbonate (also called sodium hydrogen carbonate). If you plan to use a hypochlorite source of chlorine, then you probably don't want your TA any higher than 80 ppm. You can use The Pool Calculator to calculate dosages and to verify that your saturation index is not too far away from zero assuming you have a plaster pool surface. You might increase your Calcium Hardness some, but if you adjust your TA then it's not out of line unless your pH is going to be on the low side (usually it isn't if you are using a hypochlorite source of chlorine).

You don't have to worry about phosphates. If you maintain a Free Chlorine (FC) level that is at least 7.5% of the Cyanuric Acid (CYA) level, then you will prevent green and black algae from growing regardless of algae nutrient (phosphate, nitrate) level.