CH and CYA driving me crazy!

[Illupo]

I did a complete refill last July. My CH was reading about 300 and CYA I brought up to 50 and it has consistently stayed there...till a couple of weeks ago. CH has been continuously going up and now reads 700. CYA now reads less than 20???

I thought that CYA does not go down without draining and refilling, which I have not done since last July. My CH has been steadily going up from 300 to the current level...why?

Current readings are: TC 5.0
PH 7.6
CH 700-750
CYA less than 20

The only new water it gets is to keep the level up, no refills. The CH coming from the tap is 300. So my question is: do I do a refill to get the CH back down or just add CYA to bring that level back up? The pool was last resurfaced 9-1996, and there are some areas of plaster that have deteriorated. Could this account for the meteoric rise in CH? I know that it is time for a replaster, but was hoping to wait just a while longer. I don't want to waste the stabilizer if I am needing to do a refill. Any thoughts? The water is pretty clear but was cloudy a couple of weeks ago when I started investigating this.

 

[duraleigh]

There is no relationship between CH and CYA. They are independent. I will answer your CH question.

You are in AZ and strapped with high CH (throughout the state, as far as I can tell). It will always rise because it does not evaporate out.

Some folks have great success with capturing rainwater from the roof....CH free if you can keep the roof debris out. Making exchanges with your 300 CH tap water can help once it gets above that.

Keep your pH in the lower ranges (7.2 - 7.4) to avoid scale and pay attention to your water with frerquent testing.

 

[Illupo]

Thanks, Duraleigh. I've been doing the TFP way since Feb of 2016, and the water has never looked so good! I could read a newspaper laying on the bottom of the pool while standing on the deck! One thing I thought was that I have been using a rust and scale preventer from Blue Wave, one oz a week. I thought perhaps that this product was really doing its job and removing built up scale, thus the high levels...maybe not. I test twice a week, Sundays and Wednesdays. Seems like I add acid every week just to keep PH down from 8.2. I follow pool math, but never seem to be able to get it down to 7.2...

 

[duraleigh]

I would buy enough acid to get it into that range, regardless of how much.

Your CH is fairly high and the best way to prevent any scale formation is holding a low (7.2 - 7.4 pH.