ro/di filter replacement

I agree someone needs to put DezertRat on the payroll, he has helped me BIGTIME!!!!!!!!!!!!!

THANKS DezertRat

 

Glad I can help. I'm just returning the favor, I had lots of help years ago, more years than I can remember, when I first started out. Bck then we didn't have the equipment and choices we have today, I'm talking about 1980 when I got my first saltwater tank and got hooked!

 

That was before was born

I finally got the filters

This is my first time changing it how do I do it just un screw it and put it in?

 

Replacement filters need to be flushed first and the system disinfected.

Shut the water supply off, remove the prefilter and carbon(s) then disconnect the 1/4" line which leads from the carbon canister up to the RO membrane housing at the RO end and stick that 1/4" line in a bucket or sink. This is VERY IMPORTANT! Now add 2 to 3 tablespoons of regular unscented bleach (Clorox) to the prefilter housing and screw the empty housing back on. Slowly turn the water back on until all the housings are full and you start to get water out of the disconnected line. Shut the water off and let it sit 3-5 minutes with the bleach in it. Turn the water back on and flush until all chlorine smell is gone.

OK, unscrew the prefilter housing only and install the new prefilter. Turn the water back on and flush the prefilter for a couple minutes to remove any antimicrobial treatment it may have. Shut the water off and install the carbon block, only the first one if you have two and again flush for a few minutes to remove any carbon dust or fines so they don't foul the membrane. Install the second carbon if you have one (I wouldn't use two personallly as its a waste of money and unnecessary) and do another flush. All filters should be flushed at this point so you can now reinstall the 1'4" line you disconnected and make water.

If you are replacing the DI resin it also needs a flush so use your TDS meter and monitor the RO/DI TDS to ensure it is reading 0 before using the new water. It usually takes a gallon or so to flush most DI resins.

 

So do I need a flush kit?

 

No they are a waste of money.
Keep your waste ratio at 4:1 and thats all the flushing the membrane needs.

 

I don't want to hijack the tread but I have a question for AzDesertRat that maybe helpful for others.

My setup has one pre-filter (clear housing) and 2 carbon then DI or polisher depending on the route the RO goes, also used for drinking water. Should I replace one carbon with another pre?

 

No, I would use a single 0.5 micron Chlorine Guzzler carbon the replumb the extra housing as a second DI for the most bang for your buck.
Make sure you use a 0.5 or no larger than 1 micron prefilter though so you don't plug the carbon and render it useless.

 

How do I do that?

 

Use a measuring cup and a clock or watch and time the flow from both the treated RO/DI line then from the waste line and make sure the waste is 4 times fatsre than the treated flow or 4:1 waste ratio. Many vendors and manufacturers use a fixed type flow restrictor which can be off quite a bit depending on your particular water pressure and water temperature. Just like everything else, RO is not a one size fits all so it may require changing out to either an adjustable restrictor or a capillary tube type restrictor ($5) which you trim for your exact conditions.
Too little waste and the membrane fouls prematurely and too much waste and you reduce your GPD as well as your removal efficiency since most of the pressure is going down the drain.