High CYA

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High CYA

Postby adamrusticus » Fri 12 Jul, 2019 15:40


I'm struggling with a cloudy pool that develops algae (I think) quickly. I recently left my pool unattended for 1 week when a spike in temperature happened. When I came back to town the pool was dark green all around.

I shocked it several times and vacuumed daily. I just got Taylor k-2006 test kit and it showed normal values for everything but a CYA of over 130. What should I do?

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Re: High CYA

Postby Denniswiseman » Fri 12 Jul, 2019 16:41

Hi adamrusticus and welcome
Partial drain and refill of just over 50% subject to your water table
With a CYA of 130 you need a Slam level (Shock Level and Maintain) of 52, a minimum of 10 and a target of 17 as indicated in Chlorine / CYA Chart
I take it you have been using Trichlor or Dichlor to get such high CYA which renders your chlorine ineffective
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
Use these common products to balance your pool
Liquid chlorine (sodium hypochlorite or plain bleach)
Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
Soda ash will raise pH and TA

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