Increase Calcium Hardness?

[AZPoolDad]

Here are my numbers this morning:

FC = 5.5
CC = 0.5
PH = 7.4
CYA = 25
TA = 130
CH = 100
OCLT = 0.5
24-hour chlorine loss = 2ppm

I just did a total refill last weekend and water is crystal clear. I added granular CYA with the sock method Mon/Tues, so it has been about four days since the powder was totally dissolved into the pool, and I've run the filter a lot. I'm getting about 25 CYA and want to increase to 50, so I need about 3 more pounds, but is it worth waiting a few more days and testing it again first?

The bigger question is the Calcium Hardness. I was very surprised, since I live in Phoenix, AZ, to see only 100ppm come out of the tap, but it all depends on the time of year I guess. Do I need to increase, or just adjust pH to get my CSI into a safe zone, considering the hardness will skyrocket over the next year or two on its own?

Also, going on vacation next Friday for five days, so I'm thinking of dumping four gallons of 10% HASA liquid chlorine. Thought about tossing some pucks in as well, and calculating the slight CYA spike they will provide.

Thoughts?

 

[Patrick_B]

Welcome to TFP!
No, You need more Cya it looks like. That was ample time so I would add enough to get to 40-50.
Why do you think the hardness will "skyrocket"? I'm not sure about 100, but low CH in AZ is not uncommon surprisingly.

 

[AZPoolDad]

I just assumed through evaporation and constant topping off, especially when the weather gets hot again next year, that it will climb. It was 800-900 before I refilled the pool last week. I added 3 lbs of the 5 lb jug of CYA last week, so I'll finish off the jug today and maybe add another pound on top of that.

 

[Patrick_B]

So your fill water fluctuates that much? Perhaps it's possible you were using Calcium Hypochlorite in the past?

 

[AZPoolDad]

Before I went on the BBB method back in May, I used a Paddock Pools product called "skimmer tabs" which were chlorine tabs designed to be put in the skimmer basket. It may be that these were cal-hypo tabs. My local Paddock went out of business and I stopped using them last year, so I don't know what they were made out of. But I used a lot of them over the course of two years.

My question still remains: do I need to raise my calcium hardness if it is only 100, or just wait until it goes up on its own? I rather just keep the pH a little higher (7.7) to compensate and get a good CSI level.

 

[Butterfly]

You should raise the CH to about 250.

Can you test your fill water for CH?

 

[AZPoolDad]

I think I already tested my tap water, yes? I tested a number of times, first when the pool was half filled with tap water a week ago, up until this morning, and every time the CH is about 100. I can easily enough test it right out of the tap in my kitchen but I'm sure it will be the same. I'm just wondering if it is worth putting in CH Increaser if it will creep up on its own through evaporation and refilling under the desert sun.

My numbers as of this morning. Note the CSI:

FC = 5
CC = 0
pH = 7.6
TA = 120
CH = 100
CYA = 50
Temp = 65
CSI = -0.3

If I raise my pH to 7.8, that brings the CSI to an almost perfect -0.1. So that's why I'm thinking "why bother with CH increaser?"