I don't understand it!

[H@rry]

On 11/17/14 I installed 75 GPD Dow Filmtec RO membrane, 1 Micron Premium ROsave.Z Sediment Filter, BRS Universal Carbon Block Filter - 1 Micron. Today my TDS out of the membrane is 19 ppm. I run the flush valve for about 10 seconds every time I turn it on. I normally run it 3 times a week and I don't leave it on all the time because the ATO will cause it to start and stop often when the reservoir is full. I figure in that time frame I have used 625 to 650 gallons. Something's changed! I just don't understand it.

 

[gcrawford]

You have way more experience than I, but I never flush for less than 60 seconds. I'm running a BRS 5 stage going on 3 years and have not replaced the RO membrane yet. I replace the rest of the cartridges about every 6 months and the DI resin about every 3 months. Granted I only measure before and after the DI, but I never go above 1 ppm to the brute can. I've heard that it can extend the DI resin by installing a dump valve before the resin while the TDS reading is high upon start-up. Maybe that could help...

 

[hawkinsrgk]

Hi Harry

Something is definitely up with the water in Huntsville.

After moving from Huntsville to Birmingham my DI resin last probably 5 times longer

I replaced my membranes when we moved about 3.5 years ago and the water coming out of the membranes is 2-3 ppm

Just wanted to share that I saw the same kind of thing when I lives up there

Thanks
Randy

 

[gcrawford]

To clarify, I'm on Harvest-Monrovia water, not Huntsville Utilities. Maybe they switched to chloramines....

 

[H@rry]

I have spoken with Huntsville Utilitites and they say that they only use Chlorine. This has been a problem for the past 3 - 4 years. Prior to that a membrane would last over 2 years.

 

[gcrawford]

Lead pipe from meter to house? My mom had to replace hers a year or so ago. A tree root penetrated it and caused issues. Just throwing ideas out....

 

[H@rry]

Lead pipe from meter to house? My mom had to replace hers a year or so ago. A tree root penetrated it and caused issues. Just throwing ideas out....

Same pipe that's always been there.

 

[pickupman66]

Have you tested for chloromines?

 

[Chameleon]

Sounds like a bad membrane. I am under the impression that the bouncing on and off that can happen with a float valve when the reservoir is full can shorten a membranes life. I always time mine now to prevent this but keep the valve there as a backup. BTW I recently got a spectrapure select 99% rejection rate guaranteed membrane and after flushing my TDS out of the membrane is 0-1.

 

[H@rry]

How long to you flush?

 

[Chameleon]

How long to you flush?

To tell you the truth I dont flush it but the TDS coming out is high (20-40ppm) for the first minute or so due to the brine passively diffusing when the water is not moving. It drops progressively for the first minute or so and bottoms out at usually 0. It shortens the life of my DI without flushing but I dont think it hurts the membrane and with 0-1 TDS off the membrane I'm not too worried about the DI life being shortened a bit.

 

[H@rry]

I suspect some of my problem is that when I leave the RO system running overnight it fills the reservoir and then the ATOs kick in and out until I turn it off in the morning. This will cause the RO system to start and stop several times. I'm going to start unplugging the ATO pumps while the RO system is running to see if that might help. I know that is not the total solution since I was having a problem before I installed the ATOs but it might help a little.

 

[Jason_R]

H@rry -- I am not sure what you were getting on the TDS meter before, but you do not mention if you use a DI cartridge. In my experience, if you use an RO membranea only, you will get a reading around 10-20ppm. In my past experience, it took adding a DI cartridge to get the water to around 2-3 ppm. We are on Huntsville Ultilities water, and the tap water readings here are around 100-150ppm without filtration.

 

[H@rry]

I've got 2 DI cartridges. The problem is that the RO membrane is not lasting as long as it used to and it rapidly depletes the DI resin.

 

[Chameleon]

I know chlorine is bad for membranes and if you dont keep up on your carbon block changes chlorine will make it to the membrane, but I am sure you are keeping your carbon block changes consistent with before however I am not sure if chloramine changes things or if it is in your water.