Just returned home from vacation - CC 6.5

[jmaupin613]

Hey all! I just got back from a week-long vacation and came back to find the pool clear, but upon testing, it looks like the CC is rather high. Before leaving, I tested everything, made sure the CYA was level around 50, raised it to SLAM level, then left quite a few chlorine pucks in the automatic chlorinator set to high so that there would be some chlorine added while I was gone. I never use tricolor tabs, but figured it was the easiest way to keep a little chlorine in there while I was gone without having someone to and dump liquid chlorine in. Also wanted to raise my CYA to ~60 anyways so figured it wouldn’t hurt for a week.

The pool itself looks clear…maybe a tiny bit foggy in the deepest end, but other than that everything looks fine and there is no visible algae.

What would cause the sudden high CC levels while I was gone?

0.5FC
6.5CC

Taylor 2006C test kit

 

[mknauss]

Welcome to the forum!
Check your testing method. That level of CC is not possible without chemical additions (things you should not add to a pool) or eliminated ammonia.

Add 10 ppm FC worth of liquid chlorine. Let that circulate a couple hours and retest.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

 

[jmaupin613]

Welcome to the forum!
Check your testing method. That level of CC is not possible without chemical additions (things you should not add to a pool) or eliminated ammonia.

Add 10 ppm FC worth of liquid chlorine. Let that circulate a couple hours and retest.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

Thanks! The only chemical I use is bleach. I’ve had the kit (not the same reagents) for three years and never encountered this before. Do you think maybe something is up with the reagents?

 

[mknauss]

Be thoughtful on doing the test.

Add the liquid chlorine.

 

[jmaupin613]

Be thoughtful on doing the test.

Add the liquid chlorine.

Hey! I added 3 gallons of bleach (12%) about 30 minutes before your original reply which should’ve brought things up to SLAM level or a little above.

Just re-tested now:
FC 0.0
CC 3.5

It seems like something is causing the chlorine to be used at a much quicker rate than it should be?

 

[PoolStored]

Ammonia. Continue to add 10pm of LC until FC holds at least 3ppm. Then test your CYA, will likely be gone.

 

[mknauss]

Your FC dropped to zero while you were away, a bacteria invaded the pool water and has consumed some or all of your CYA. The result is ammonia in water as @PoolStored said.

 

[jmaupin613]

Your FC dropped to zero while you were away, a bacteria invaded the pool water and has consumed some or all of your CYA. The result is ammonia in water as @PoolStored said.

This also explains why my CYA is now testing as ~20.

Thank you both for the help! I appreciate it!