Pool Still Green After 2+ Weeks

[madlakespool]

Good morning all!

For reference, I have a 27000 gal IG Concrete pool with a Triton II Sand Filter and Pentair CHII N1 Self Priming Pump (10+ years old). The main drain doesn't work.

About 2.5 weeks ago, the water started turning green. I jumped on here to get some advice/info and started following the SLAM process. Unfortunately it is not working. I have tried shocking, clarifier, algaecide on top of vacuuming daily, using the broom, backwashing, etc. and nothing is clearing the water.

My readings are
TC: 6.0
CC: 5.0
Alkalinity: 140
CYA: 90
pH: 7.6

Any advice is welcome at this point.

 

[woodyp]

Welcome. To what level did you maintain your FC at while doing the SLAM?

 

[JJ_Tex]

You need more chlorine and/or drain water to lower your CYA. Use the chart below for the correct amount. At CYA of 90 your target FC for a clear pool is 10-12, and slam level is 35. You are at 6.0.

Also, use liquid chlorine as that does not have CYA (pool shock adds CYA which likely contributed to your high CYA).

Chlorine / CYA Chart - Trouble Free Pool

 

[jimbethesda]

What test kit are you using? I noticed you reported Total Chlorine and combined chlorine. If those numbers are correct, your free chlorine is only 1. Well below slam level and also below the recommended minimum.

 

[jimbethesda]

I see your test kit in your signature now. You need a FAS DPD kit to properly test for chlorine. Your issue is that you haven’t been slamming at all.

 

[madlakespool]

Ah! I didn't realize. Is there a specific test kit you recommend?

 

[jimbethesda]

Since you already have a test kit, you just need to add one of these:

FAS/DPD Chlorine Test Kit

tftestkits.net

Amazon.com : Taylor K1515A Drop Test Swimming Pool Free & Combined Chlorine FAS DPD Test Kit : Swimming Pool Maintenance Kits : Garden & Outdoor

Amazon.com : Taylor K1515A Drop Test Swimming Pool Free & Combined Chlorine FAS DPD Test Kit : Swimming Pool Maintenance Kits : Garden & Outdoor

www.amazon.com

I also recommend getting the speedstir, it makes all your testing easier:

Taylor 9265 Magnetic Stirrer Speedstir Start-Up Pack w/ Stir Bar + Batteries: Swimming Pool Liquid Test Kits: Amazon.com: Industrial & Scientific

Taylor 9265 Magnetic Stirrer Speedstir Start-Up Pack w/ Stir Bar + Batteries: Swimming Pool Liquid Test Kits: Amazon.com: Industrial & Scientific

www.amazon.com

TFtestkits.net

tftestkits.net