mine was doing this last week.
is your waste water still flowing at a good rate?
how old is your system?
mine was two years old, i had a similar problem, my production went down to less than 100 ltrs in 24 hours.
i have now changed the membranes and production is right back up to max again.
consult RO man via e mail, thats what i did, and had it sorted within a few days.
i know people moan about there customer service, but i've always found them to be very helpful.
goodluck