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View Full Version : when to replace RO/DI cartridges

pogiboy67
10/04/2006, 12:47 PM
ok my RODI unit is outside and now i see that there is algae growing inside the units. Is this something i want to replace now? or is it ok to still use?
MCary
10/04/2006, 01:16 PM
If I had a unit outside I would cover it with tin foil so light couldn't get in. Gunk is not good. It will prematurely clog your prefilters.
papagimp
10/04/2006, 01:40 PM
It's best to use a TDS meter to accuratley judge when cartridges need replacment. I found that out the hard way when my freshwater tank (usually kept at 6.4pH) was running close to 9pH. I'd second covering up the unit and keeping light out.
smleee
10/04/2006, 01:57 PM
Pre-filters should be replaced every 6 months regardless of usage. RO and DI can be replaced when your TDS meter tells you. Yes, the light is bad - that is what is causing the algae.

eee
AZDesertRat
10/04/2006, 01:57 PM
Very bad. You are running the risk of bacteria and virus growth. Disassemble the unit completely including removing the membrane and disinfect the housings well before installing all new filters. Move the unit to a protected place away from any temperature extremes and direct lighting or you will be back here all over again. Prematurely clogging the filters is the least of your worries, sickness is a very real concern either for yourself or your fish.
A TDS meter will only tell you when to replace the membrane and the DI but does very little for diagnosing pre and carbon filters. Replace pre and carbons every 6 months or sooner in special cases and replace the DI when you see a rise in final TDS above what you think you are comfortable with. I replace DI resin at a reading of 2 TDS or less.
pogiboy67
10/04/2006, 02:13 PM
THANKS ALL i will be replacing them
pogiboy67
10/04/2006, 02:17 PM
btw how do i disinfect the housing?
AZDesertRat
10/04/2006, 02:21 PM
Most RO/DI vendors have directions on their sites but basically you remove all the filters including the membrane, put 2 spoonfuls of regular unscented bleach in the first housing, open the inlet valve and slowly fill up the housings and run it all to waste until its completely gone before reinstalling all the filters. Never let any bleach get near the membrane or its toast.
pogiboy67
10/04/2006, 02:23 PM
thanks guys... I got my stuff from buck eye field supply... will be placing an order today
AZDesertRat
10/04/2006, 02:29 PM
Good vendor, Russ will take care of you.