how often do you change your r/o filters?

[smitten with ocean life]

just came in from busting my knuckles changing the filters on my r/o system. the first filter is always the grossest. the next 2 are hardly bad at all- just the part facing out is slightly green. i always change all 3 filters at the same time. but i am kind of wondering if that is necessary. does it work to just spray off the last 2 filters and keep using them? i change them when the tds starts climbing. thoughts?

 

[slingfox]

just came in from busting my knuckles changing the filters on my r/o system. the first filter is always the grossest. the next 2 are hardly bad at all- just the part facing out is slightly green. i always change all 3 filters at the same time. but i am kind of wondering if that is necessary. does it work to just spray off the last 2 filters and keep using them? i change them when the tdi starts climbing. thoughts?

I believe the rule of thumb is you should change the sentiment filter (the first filter) twice as often as the carbon blocks (the 2nd and 3rd filters). The RO membrane which comes after should theoretically last several times longer.

I can’t remember if it is for the sentiment filter and/or carbon blocks but if you see the pressure on your RODI unit decline materially then it is time to change filters. This is not relevant for me since I have a booster pump so the system is always pressurized.

For the carbon blocks you can test with chlorine test strips and if it shows up then replace them. For the RO membrane you check the incoming and outgoing TDS and replace when the performance doesn’t perform in-line either the specified rejection rate. For the DI resin you change when the final output TDS is greater than zero.

 

[smitten with ocean life]

thanks! now im wondering if i should go dig those filters out of the trash now ive always wondered- does it help to keep the whole system out of the sun so it doesnt grow green so fast? or does shade make it worse? im in a temperate zone so i dont deal with real hot or cold weather. i currently keep the system in the garage but have wondered if i could just mount it outside out of the sun

 

[KStatefan]

When they need it
Sediment based on pressure drop
Carbon based on how many gallons
Membranes when rejection rate drops below 97%
DI color change and TDS number

 

[BeanAnimal]

I tend to not look at them or the TDS meter. That way they don't need to be changed.

 

[Tangdora]

I just buy my filters in bulk to save on cost. Packs of 6 (sediment, 10 micron carbon , 1 micron carbon, di resin) on amazon and change all 4 as soon as my tds shows greater than 0 , im on well and they only last about 2 months.

 

[smitten with ocean life]

I tend to not look at them or the TDS meter. That way they don't need to be changed.

fair enough!

 

[mfinn]

I used to change out my sediment filter about every 3 carbon block changes. That was because they barely changed color. From a bright white to a barely yellow. But in the last few months my sediment filter has turned dirty brown in maybe 100 gallons of product water made. Something has happen with the local water system. ( I sent a email to the water company last week)
My carbon blocks got changed every other di resin change out.
My di resin got changed when the gauge started showing 1. Usually I would wait until the container was filled. Then I would swap the second di container to the first spot and fill the second container with new resin.

 

[smitten with ocean life]

wow. ok!

 

[EricR]

I go with:
Sediment filter -- when it starts to look a little dirty. (They're cheap in bulk anyway).
Carbon blocks -- test total chlorine in waste water and look for pressure drop going to RO membrane.
*have actually never seen any sign of chlorine or pressure drop but feel obligated to change anyway some time after 1 year (maybe 1.5 years)
Mixed-bed color-changing DI resin -- can see when expended. I swap the OK 2nd one to 1st position and put new resin in 2nd position (like mentioned in post# 8).

So far, I've never seen anything above 0 TDS on final output from inline meter or using handheld meter.

 

[smitten with ocean life]

well, im not sure what to think now. changed all that and the TDS is still at 6-7 after rinsing it out

 

[slingfox]

well, im not sure what to think now. changed all that and the TDS is still at 6-7 after rinsing it out

Did you change the RO membrane and DI resin chambers too?

 

[smitten with ocean life]

those are the ones on the top? no because i did those not too long ago

 

[slingfox]

those are the ones on the top? no because i did those not too long ago

What is the TDS going into the DI?

 

[smitten with ocean life]

ill check tomorrow. im winding down for the night