Oakland/SF Tap Water

[Srt4eric]

Follow up question: Do they really last longer though with all the unknown aspects you mention? I still replace mine relatively frequently which might not be needed but your response rather confirms that I want to continue doing that.

I know my color changing resin burns up every hundred gallons or so. 300-450 tds out of the tap

 

[Patio]

Same in Livermore and I have high co2 so really burn through anion. Splitting anion and cation has helped the pocketbook. Then I have a mixed as the last stage. Bought the chloromine monster before realizing it is probably the co2 levels burning media. But like the extra piece of mind from the monster.

 

[sfsuphysics]

I will probably need to look into this more. The Fauna Marin ICP Total test measures RODI water quality and it has not detected anything in the past 4 or more tests, but I am not doing it as sophisticated as you are, so I wonder if there is room for improvement.

My schedule looks like this:

DI resin replaced every 12 weeks
RO membrance replaced every 52 weeks
Sediment and Carbon plus replaced every 20 weeks

I believe this was determined based on the manufacturer recommendation plus some buffer since I do not know the amount of water this is producing.

1 year seems awfully frequent for an RO membrane, but then again I don't know how much water you're making either.

"Easy" way to determine is for sediment/carbon, look to manufacturer's specs, and change it as recommended with a flow meter hooked in (I know.. more equipment), remember total flow in not just how much water was made, now things like dirtier than normal water obviously trumps total gallons (rusty pipes, plumbing recently done in area, etc), so if you have the clear housing for your filters (my recommendation) you can give it the eye ball test. Do note that chloramine rating is different than chlorine rating for carbon filters too, like significantly less than chlorine.

RO membrane is simple, have an inline TDS meter and occasionally take a look at the numbers, replace when the TDS is significantly higher than when it was installed. I would say with proper back flushing you should get many years out of the membrane though. Also keep in mind TDS when it first turns on will be higher than after it's been running a while.

Resin... color change is a nice indicator... well except for me because I always forget what color it started at. But again, inline TDS after the resin and when it the number gets too much above 0, swap it out, if you're like me who runs some complicated setup of multiple resin types throw in an inline meter after each part. 3 input devices are common

 

[PjFish]

Curious what micron size pre sediment filter people are using? I know this may very depending on location.. I use 1 micron which lasts a while and change when pressure drops..I do see alot of people using 5 micron though..

 

[Darkxerox]

Curious what micron size pre sediment filter people are using? I know this may very depending on location.. I use 1 micron which lasts a while and change when pressure drops..I do see alot of people using 5 micron though..

I use 1 um since I don't really have any pressure drops using it and at least that size can protect the membranes more. I think if you have more turbid water coming in e.g. well water or pipes that shed fragments, then the 5 um pore size might clog less. They're so cheap compared to the RO membrane that protecting it really is worth it.