High combined chlorine

[dukie564]

Got the pool topped off, cover off, and pump operational a few days ago. Hit it with a shock of liquid chlorine and again 2 days later.

Starting numbers:

FC: 15.5
CC: 4.5
pH: 8.0+
CYA: 30ish


Should I be concerned about the high CC number? Will the sun do the work for me?

It was steadily rising toward the end if last season (had to use Trichlor tablets due to running out of liquid chlorine). Only thing I put in at closing was algecide.

 

[JamesW]

You need to SLAM. If your CYA is a lot lower than at closing, you might have ammonia.

 

[woodyp]

That pool needs a full on SLAM per Pool School. I'd lower ph before I started it.

 

[dukie564]

Been SLAMing for 3-4 days now. CCs dip slightly in my morning test but are higher in the evening, and on the rise!

FC = 16
CC = 5.5
pH = 7.3
Cya = 35

My CC reagent is 2 years old now. Thinking the test may be off...ordering new chemicals to rule that out.

Any reason why this could be happening? It was super sunny the last couple days and I expected the CCs to burn off...and FC level has been kept at shock level

 

[Casey]

What's your water look like? When adding chlorine, does the shock level drop quickly, within the hour?

- - - Updated - - -

Hit it with a shock of liquid chlorine and again 2 days later.

SLAM'ing the pool needs to be done consistently by not letting the levels drop dramatically for any length of time. Bring it to SLAM Levels and keep it there. You will never bring down the high CCs otherwise. In fact, you're only wasting your chlorine.

 

[Flying Tivo]

I suspect its the reagent, or you are waiting too much time after the FC test to do the CC test.

Felipe

 

[dukie564]

Water is crystal clear. FC level is pretty consistent overnight. I've been maintaining FC shock levels for about a week now. CC test done immediately after the FC test

 

[dukie564]

Just to update, I got my new DPD Reagent yesterday. Tested CC and it's zero. Old bottle being expired threw the test off