RO on the fritz. Suspects?

[Capt_Cully]

It's making water with 0 tds, but the waste water is running at a much higher volume. Production rate is less, so that adds up. When I go to flush it, no water flows.

Anyone have any input on where the clog might be? I'd hate to go through a 2 day trouble shoot, or to completely tears the thing down if someone thinks they know what it is.

Water general. 5 stage. 75GPD membrane with flush kit.

Thanks!