No RO waste H2O

Hi all...long time, no post...
Things have been going fine with my reef...I actually picked up a couple frags when I brought in some BTA to my LFS...
Anyway, when I was making my latest batch of RO water I noticed that I wasn't getting any waste water from my Kent Hi-S RO unit. Odd, I thought. I also noticed that the micron filter was loverly shade of cruddy yellow-brown. Which reminded me that I'd REALLY been meaning to replace those filters. Maybe the filters were so clogged that it was mucking the flow up. So I picked up a carbon filter and a micron filter (Coralife, but they fit) and replaced them this afternoon. I fired up the RO unit and once again I'm only getting flow from the good RO line, nothing from the waste line.
Any thoughts on what's going wrong here?
Thanks much!
-E-

 

Long time no chat, glad to see you back and the tank is fine. Do you have any valves that have got closed by mistake??? What are your TDS's? I wonder if it's your membrane.

 

TDS: 142 in, 54 out. (that's assuming that the meter on the unit works...i have no idea what values i should be looking for)
Do you mean valves on the unit itself? If so, I wouldn't know where to look for one so I wouldn't think I managed to close one. Is the membrane in the top, horizontal white tube?

 

One more note (if it helps w/ diagnosing the problem): when i disconnected the input line from the sink adapter there was quite a bit of backflow. That is, when I took the tube off the tap, water flowed back UP the line from the RO unit and out into the sink. Never seen that before...

 

I think your membrane is spent. Thats a nutty amount of tds.

 

You should be getting around 0 tds coming out of the unit. It might be time for a membrane change.

 

You also need to make sure there is no obstructions on the waste water side. There may be something that is stuck in the line. Take it off and blow it out or just take it off at the unit and see if you get waste water. Plus railroader is correct there should be NO TDS's on a reef tank. Do you have a DI unit on the system?

 

All very good information and all greatly appreciated.
But, GAH membranes aren't cheap...and how do I figure out how many gpd the unit is rated for? I can't find any indication anywhere on it........

 

I have a 100gpd unit but I put a 75gpd membrane in it because the H2O guru doesn't recommend anything higher. Have you looked on the internet anywhere?

 

Did you run the whole line and make sure there isn't a kink in it somewhere?