Tired of bad advice from pool company

[keith]

Hi - in response to your last post, I've drained and refilled. Here are my numbers after refilling based on my K-2005 Taylor test kit. To recap it's a 28K gunite in-ground pool

Free Chlorine - 1.0
Combined Chlorine - 2.0
pH - 8 (acid demand was 2 drops)
Total Alkalinity - 120
Calcium Hardness - 160
CYA - 0

Again my goal is to use the BBB method to balance the water. Your help is most appreciated!
Keith

[PoolDoc]

Did you get a K2005 or a K2006? There's a BIG difference!

Anyhow, get some acid and bring the pH down. Don't worry about acid demand; just add a small dose and repeat till you get there.

If you are going to use bleach or cal hypo, add CYA -- 1# will add about 4 ppm if fully dissolved.

If you are going to use dichlor or trichlor, add less CYA, probably only 5#.

Dunno why you have CC -- unless you've got a K2005. DPD tabs are a pain.


Ben

[CarlD]

Two good things about a gunite pool:
1) It can stand very acid water without melting the liner (vinyl is in danger once you go below 6.9)
2) It can stand VERY high chlorine levels, like 50ppm or more (where vinyl will bleach). This is good for clobbering algae but you still can't swim till it comes down to levels Ben recommends.

Now that your pH is high and your stabilizer (CYA) is zero, Trichlor tabs and/or dichlor powder is a good option. Both will lower pH and raise CYA levels.

But with Gunite, your cal is below the recommended 200-400ppm. Cal-hypo is a good chlorinating option for that as it adds calcium.

Personally, though, even with gunite, I'd worry about calcium levels last.

BTW, when your pH is at 7.6 or lower, your T/A will measure lower too, but it should be fine.