I have the Aquatic life rodi delux unit and I noticed my tds were getting pretty high so I replaced the three cartridges. After I replaced them my tds were 15 so yesterday I replaced the di membrane and now it is testing higher. The tds started out 50+ and now that I have gone through 40 gallons of water the tds are reading 26, should I continue to burn water hoping they come down more? Is this normal for a di mdmbrane to take so long to break in?
rodi replacement
- Thread starter bigpaul
- Start date
there is not necessarily a problem. So many variables at stake and TDS is only a ballpark measurement.
ensure the following:
- membrane housing is tight
- membrane is in good condition
- membrane rating is 96% rejection or better
- waste water restrictor is installed correctly
- waste water restrictor matches GPH rating of membrane
- all connections throughout system are tight and leak-free
- input water is relatively good (less than 500 tds)
- pre-filters are relatively new and rinsed.
- tds meter is relatively accurate (best to have two to compare)
- tested water is collected after few minutes of running system.
- tested water is collected in absolutely clean container.
- ASOV valve is installed correctly (numerous diagrams available via internet)
there are more but this just off the top of my head
hope this helps
K. Adams - Marine Aquarium Expo
-
ensure the following:
- membrane housing is tight
- membrane is in good condition
- membrane rating is 96% rejection or better
- waste water restrictor is installed correctly
- waste water restrictor matches GPH rating of membrane
- all connections throughout system are tight and leak-free
- input water is relatively good (less than 500 tds)
- pre-filters are relatively new and rinsed.
- tds meter is relatively accurate (best to have two to compare)
- tested water is collected after few minutes of running system.
- tested water is collected in absolutely clean container.
- ASOV valve is installed correctly (numerous diagrams available via internet)
there are more but this just off the top of my head
hope this helps
K. Adams - Marine Aquarium Expo
-
This morning I double checked all connections and there are no leaks and all plumbing is correct. I replaced the 3 pre filters about a month ago a the di membrane two days ago. I was hopping after replacing everything that my tds would be closer to zero and not be higher than they were with the old filters. I do make about 30 gallons of rodi water per week so maybe I should change the pre filters and see what happens.
thanks for your help.
thanks for your help.
so let me see if I understand what your said. you changed the 3 pre filters, and the di, that's good. but those don't do anything if the actual RO membrane is old and needs replacement. (that's not one of the 3 you said you replaced.)
test water after the RO membrane and before the DI. whats that tds. should be low like around 10 or so maybe. then after the Di should be like 0. if not as stated above replace you RO membrane
test water after the RO membrane and before the DI. whats that tds. should be low like around 10 or so maybe. then after the Di should be like 0. if not as stated above replace you RO membrane
Last edited:
I still do not get what your saying or you don't get what im saying. you said "DI membrane" in an earlier post... there is no such thing. only a DI cartridge or DI bed or whatever. The RO membrane (reverse osmosis) is completely different then the DI cartridge. maybe you mis-spoke? what GPD did you replace it with? did you change the flow restrictor to match the new flow rate? that's very very important.
You are right I did say di membrane when I meant ro membrane, sorry for the confusion. The unit itself is a 90 gpd and the ro membrane is rated at 100gpd. I am not sure which flow restrictor is in there but I will find out tomorrow and if needed order a new one. I did notice that my gallons per day has increased quit a bit, I was getting about 32 gallons a day and now it is 32 gallons in a few hours.
You are definatly having a problem with membrane or flow restrictor, I had a cracked housing on membrane one time. When you get your restrictor sorted out check that you are getting 1 part water on your output line and 4 parts out your drain line. It is easy to check with two similar size containers. The three carbon blocks before your membrane do nothing to knock down TDS they just keep large particles out of membrane and pull Chlorine and Ammonia from water. They are probably still good, but should be replaced every time you change your DI.
Important if you were getting high TDS out of your DI those cartridges are done and need to be replaced. Your membrane when set up properly take 96 to 99% of your TDS out and your DI takes care of the small amount left. When you have a membrane problem you can use up the DI within a few hours that is why you always want to keep eye on what is coming out of membrane.
I have upgraded my unit to Spectrapure 99% rejection membranes and I go from 300 TDS to 2 to 3, this has doubled my DI life. With that said some of my problems I think are because My Carbon will not last as long as my DI and I had Chlorine in my make up water. Conditioner can fix this problem but I will start changing carbon blocks more often in my system.
If your making water at a rate 10 times faster than before you have a cracked housing, a bad membrane, or your 1 way valve is shot???
Good luck!
Important if you were getting high TDS out of your DI those cartridges are done and need to be replaced. Your membrane when set up properly take 96 to 99% of your TDS out and your DI takes care of the small amount left. When you have a membrane problem you can use up the DI within a few hours that is why you always want to keep eye on what is coming out of membrane.
I have upgraded my unit to Spectrapure 99% rejection membranes and I go from 300 TDS to 2 to 3, this has doubled my DI life. With that said some of my problems I think are because My Carbon will not last as long as my DI and I had Chlorine in my make up water. Conditioner can fix this problem but I will start changing carbon blocks more often in my system.
If your making water at a rate 10 times faster than before you have a cracked housing, a bad membrane, or your 1 way valve is shot???
Good luck!
