High cya

NewbieJuice · May 10, 2015

Hi new to the forum and had a few questions.

I am located in Arizona and have 13,000 gallon inground plaster pool. Our pool water has been turning greenish when we add chlorine. We were originally using shock but have switched to liquid chlorine. I went to the pool store to have our water tested and he said the CYA was 160 and we needed to drain the pool after this season as it is too hot now in Az to drain it now.

I just tested our water with a taylor test kit and the fc is higher than 5 it's as high as it goes on the kit, PH is 7.2 and total alkalinity is 150ppm

Our water is green right now and always turns green after schocking or adding liquid chlorine. They tested the water for metals and they said it had none. I am not sure what the problem is or what needs to be done?

Also what are the steps we have to do to maintain our pool with 160cya and be able to safely swim in the summer. How high should FC be at and how much liquid chlorine at 10% would I need to add every few days to keep it at that level?

Please let me know any information or if you need any more information. Thanks!

Azgirl71 · May 10, 2015

Welcome to TFP! With you CYA that high you will never be able to do a SLAM. It will just take to much bleach/ liquid chlorine. The only way to lower it is to do partial drains and refills until CYA drops to 30-50 and then SLAM.

You state your water is green so you will need to SLAM. Also what Taylor kit do you have?

Isaac-1 · May 10, 2015

It also sounds like you need to add the FAS-DPD Chlorine test to your existing kit (let me guess you bought the K-2005 instead of the K-2006?) The FAS-DPD chlorine test only can be bought at TF Testkits http://tftestkits.net/FAS-DPD-Chlorine-CC-s-test-p47.html

pooldv · May 10, 2015

Chlorine level needs to be maintained based on your CYA level according to this chart, Chlorine CYA Chart. The minimum FC for 160 cya is 12, the target level is 19 and the shock level is 63. Any time the FC drops below the minimum you are at risk of algae growing. The goal is to never let the FC level drop below the minimum.

It is safe to swim when the FC level is below shock level for your cya, PH is between 7.2 and 7.8 and the water is clear.

Welcome to TFP!

Here are some intro Pool School articles
TFPC for Beginners
ABC's of Pool Water Chemistry

Here are the Recommended Levels for your pool.
Here are the Recommended Pool Chemicals
Use PoolMath to figure out how much to add.

NewbieJuice · May 11, 2015

I bought a Taylor kit from Leslie's. It dleant have the model # on it but it does not seem to have everything I need.

If my pool is clear and turning green only when I add chlorine does that mean their is metal in the pool even if at leslies when they test it it shows no metal? What would you guys recommend to treat it if it is metal? Thanks once again for the help

pooldv · May 11, 2015

I am not an expert on metals in pools. Here is an article from Pool School about metals that should provide what you are looking for and help you determine if you think it is metals.
http://www.troublefreepool.com/content/137-metals-in-the-water-and-metal-stains

Isaac-1 · May 11, 2015

I don't have a metals problem, so no first hand experience, but the Jacks Magic line of sequesterants are widely endorsed around here.

zikronix · May 12, 2015

I am also in Arizona. I doubt you have a metal problem. However I had the same cya problem you had when we moved into this house, I did a full drain, chlorine scrub and refill on my 17K plaster pool. I raised my cya to 50 afterwords other wise the chlorine just burns off to fast. Im thinking of taking it to 60 though, because I feel like im still dropping a lot of chlorine.