RO Membrane Life

[jwreffner]

What kind of life are you all getting out of your RO membranes? Especially you Findlay people??? Anyone have a TDS meter that helps determine?

Thanks,
Jay

 

[Dubbin1]

I have a TDS meter but I have not had my RO/DI unit long enough to worry about replacing the membrane.

 

[jwreffner]

How old?

 

[Dubbin1]

I think I got it around July.

 

[zaireguy]

6 months to a yr is pretty good for a membrane.But it is almost cheaper to buy a whole new unit off of ebay then to just but a membrane buy its self

Then you got a brand new unit all new filters for about the price of a new membrane.

 

[Dubbin1]

Ron, membrains last much much longer then that. I think you are thinking of the filters.

 

[zaireguy]

It depends on how hard your water is.mine here last about a yr I replace my other filters every other month they are cheap most everything I have read most people change the membrane around a yr to yr and a half.

But if youuse a tds then you can get the most life out of the filter which I my self need to get

 

[hllywd]

Mine's been up the longest Dwayne, bring your meter over this week and we'll check mine, it's 2yrs or a little more old by now.

 

[jwreffner]

I was thinking you would get approximately 2 years out of a membrane for typical city water???

 

[hllywd]

I guess I would assume the life to be much longer than you'd think, at least if you were using it strictly for aquarium use like mine. I'm sure I haven't averaged 10G/week and if you multiply that by 2 years I've made less than 1000G of finished water... doesn't seem like a lot to me...

 

[jwreffner]

So how do you all determine when it is time to replace it? TDS meter?

 

[hllywd]

Unless someone has a better idea, yes.

 

[Spuds725]

I've had an RO membrane going for 4 years-- on well water west of Toledo... it is after a water softener...

TDS of 16 ppm on RO output with 411 ppm going in.... which is a 96% rejection unit....

THis has been used for drinking water and fish make up water for the last 4 years....

I am now using a Spectrapure (RO/DI) I bought off Pferboy last summer for the fish water (still using the one above for drinking/cooking).... this one has a 98% rejection.... 411 in, 8 ppm out... TDS is 0 now... just bought new DI resin... got refillable canisters from Airwaterice.com...

I don't know if city water is harder on membranes due to the chlorine and stuff they add though.......

HTH

 

[ohioreef]

The only way to tell when a membrane needs replaced is to measure the TDS going in and the TDS coming out and determine the rejection rate. 75gpd and lower membranes should have a 96%+ rejection rate. If it is lower than that then it is probably time to replace the membrane. 100gpd membranes should have a 90%+ rejection rate.

One suggestion, allow it to run for several minutes to remove all the elevated TDS that happens when you first start it up. My membrane will read around 100TDS when first started but after a couple cups of water the TDS is around 18, that is with around 400TDS going in.

 

[jwreffner]

Guess I will buy a TDS This hobby get's more expensive all the time! But I do see that SpectraPure has the same TDS meter as MarineDepot but for $25 instead of $40.

Jay