Barely a chlorine reading

[Tmcarbone]

What would be a reason for not getting a chlorine reading?
Every time I test our pool water the FC is always very low. The pool is clear and looks great. I would never think anything is wrong with it until I take it to the pool store to test it.
Here are my latest numbers:
pH = 7.6
TA = 81
CYA = 37
FC = 0.2
TC = 0.4
Phosphates = 0

I use chlorine tabs in an auto feeder chlorinator. I either use liquid chlorine or granular shock (has calcium hypochlorite ) to shock it weekly.
Any suggestions on how to get a reading on the chlorine?
Thanks

 

[YippeeSkippy]

You've got something in the pool chewing up the chlorine.

Those test numbers are pool store numbers, right?? You need to test yourself, as we don't trust pool store numbers; Take 3 samples to 3 unrelated stores and you'll get 3 different answers.

How's the water look? I'd say add a gallon of liquid chlorine in there and order up a test kit. Stop doing weekly shocks as they're not helping you, and may be causing more problems.

Be careful using pucks as they allow your CYA stabilizer level to leap up too high in a flash. The higher the CYA means you need more chlorine to balance and sanitize the water. See this --> FC/CYA Levels

Have you had a chance to read some in PoolSchool? This is a good starting point --> ABCs of Pool Water Chemistry

TF-100 test kit is my choice- www.tftestkits.net

Maddie