36 bit high really. would expect it to be less than 10 depending on pressure etc.
have you flushed it first?
how much waste percentage to pure? if you have Di vessel then that should be bringing it down after anyway.
also perhaps membrane not fitting properly.
either way this level of tds isn't good. actually, that is depending on your filters, I was presuming you had 4040, but if it's Merlin or other sort maybe this is not so bad.
hope some of this helps!