new River Rok pool, can't brush away DE

[swampromeo]

I just recently installed a 15000 gallon pool and wanted a "lagoon" appreance, I choose River Rok's Emerald Black as the finish. During the first days of brushing the pool, the DE used was brushing up with each push of the brush. One day the temp here in S. Texas dropped to 36 with the water temp dropping from 68 to 48. I now cannot brush off the DE and it is a lighter color than some of the Emerald Black finish, it apprears streaked. pH=7.6 CL=1 to 1.5, water temp= 65. Any suggestions?

[BilliBob]

Lower the ph and try brushing again.

What are your other numbers?
TA
CH