no Chlorine - Help!!

[CJDahl]

i am having difficulty maintaining chlorine using Dichlor . 37500 gallon pool ..For multiple days I put in 32 oz of Dichlor and next day Chlorine reading 0 - 0.50 (taylor kit and pool store readings). Pool is crystal clear but essentially no Chlorine. my dealer said i had "chlorine lock" and had me put in a few gallons of shock.. no change.... thank you in advance for any suggestions!!

Temp 71
PH 7.6
FC 0
CC 0
ALK 150
CH 235
CYA 145

[CJDahl]

I am going to do a reset and replace some water ... about 12-18" which i figure is about 20-30% of total .. does this action make sense? thank you in advance for thoughts!!

[Pappy]

Have you checked your combined chlorine levels early in the morning, before natural UV light can burn it off? And have you diluted the water 1/2 & 1/2 to check CYA levels? Above 100, accurate results are difficult at best. How are you getting your numbers? Pool store, Taylor test kit, telepathy? If you want good solutions, you need to provide complete and accurate info.

[CJDahl]

Thank you for assistance.. I did replace about 20% of water on Saturday.. and let pump run overnight . Levels on Sunday are listed below (readings from pool store using fancy equipment , but consistent with my own measurements using taylor kit).. I am putting in ~80 oz of dichlor into 37500 gallon pool (about 2 oz/1000 gallon) and chlorine still totally dissipated after a day. At the direction of pool store this time I deployed chlorine directly to the deep end ( i had been feeding through skimmer) ... One other piece of info is I am using Nature 2 cartridge.. is it possible Nature 2 did not activate? Thank you in advance for assistance!!

FC 0
TC 0.02
CC 0.02
pH 7.7
Hardness 167
Alkalinity 123
CYA 96
Copper 0.1
Iron 0.1
Phosphate 320 ppb

[CJDahl]

added 4lbs of 73% Cal-Hypo a few days ago.. all appears well... I believe this was a Nature2 issue.. glad I figured out!