Your not supposed to run hot water through the ro filter.
From Filmtec product specs
http://www.dow.com/PublishedLiterat...seps/pdfs/noreg/609-00055.pdf&fromPage=GetDoc
Effect of temperature
As Figure 3 demonstrates,
membrane productivity is very
sensitive to changes in feedwater
temperature. As water temperature
increases, water flux increases
almost linearly, due primarily to the
higher diffusion rate of water through
the membrane.
Increased feedwater temperature
also results in lower salt rejection or
higher salt passage. This is due to a
higher diffusion rate for salt through
the membrane.
The ability of a membrane to
tolerate elevated temperatures
increases operating latitude and is
also important during cleaning
operations because it permits use of
stronger, faster cleaning processes.
This is illustrated by the comparison
of the pH and temperature ranges of
FILMTEC? FT30 thin-film composite
membrane and a cellulose acetate
(CA) membrane in Figure 4.