You need a proper way to test for chlorine--and you need it ASAP.
I suggest you go online to Leslie's or Taylor and order a FAS-DPD chlorine test kit, or a full service test kit that uses FAS-DPD for testing--Both have just the chlorine test, but you can also get a full kit likea Taylor 2006 kit or a Leslie's "Chlorine FAS-DPD Service Test Kit" and have it drop-shipped for overnight delivery.

This will allow you to accurately measure Free Chlorine and Combined Chloramines separately, and measure each up to 50ppm.