What's the deal with my RO

[platax88]

I have been going through tons of di resin lately. So i tested the water coming out or the ro membrane (before going into DI).

Here are the numbers:

Tap = 278ppm

After RO membrane = 172ppm

After DI = 0 ppm

It seems to me that the ro membrane is faulty, because it should be removing 99.9% correct? This was replaced about a year ago. Don't know why it would have become damaged. Any ideas?

[reefergeorge]

I'm not an expert, but what is your pressure, and waste water to good water ratio??
This could help find out if you membrane is shot, and why.

[platax88]

My preassure is 70psi ... i have not measured the ratio but i think i need to do that.

I'm pretty sure that the membrane is shot

Thanks!

[AZDesertRat]

Have you kept up with the filter replacements and always used high quality replacements? You haven't tried blending hot and cold water have you?
It sounds to me like your membrane is shot due to either chlorine damage or hot water damage.
The RO alone will not get you 99.9% removal, but it should be in the 96-98% range if its a 75 GPD an 88-90% range if its a 100 GPD.

Usually if you have low pressure or the waste ratio is too low for a significant period of time you will notice a drop in production not a major increase in TDS. In the case of low waste ratio you may get increased production for a limited time then the production will drop due to a plugged membrane since it has not been continously flushed well. The membrane may eventually rupture but there would be little reduction in TDS, major GPD out the good line and probably no waste at that point.

[[17]shawn[17]]

stupid question but its has happened before, are you sure there is a ro membrane in there?

your sed and carb could be taking you down to the 172 and your DI to 0

[AZDesertRat]

Sediments and carbons do almost nothing for TDS, they are there to protect the RO membarne which does remove 98% of the TDS. remember TDS is Total Dissolved Solids, prefilters remove TSS or Total Suspended Solids, much much larger particles.
You probably will not see a TDS reduction of more that 2 or 3 after the prefilter and carbon nowhere near the 172.

[platax88]

AZDesertRat -- actually the last replacement was THIS KIT ... so a pretty cheap route. The unit is plumbed just to cold water.

I've never heard of chlorine damage, how can this be avoided, i wonder if this is my issue since my DTS coming out of the tap is so high. Also, i do not ghave a flush valve, could this be another reason it went on me?

Looking (not meassuring) at the waste/good ration it seems about correct to my eye.

[platax88]

Originally posted by AZDesertRat
Sediments and carbons do almost nothing for TDS, they are there to protect the RO membarne which does remove 98% of the TDS. remember TDS is Total Dissolved Solids, prefilters remove TSS or Total Suspended Solids, much much larger particles.
You probably will not see a TDS reduction of more that 2 or 3 after the prefilter and carbon nowhere near the 172.

ok, i just looked at my records, and i have not changed the carb and sed for a year and a half

Maybe this is why the RO is shot??

[AZDesertRat]

Could be but that carbon block should be good for at least total 5000 gallons of chlorine at 1 mg/L. Thats 4000 gallons of waste and 1000 gallons of RO/DI water. Its possible you made this much over an 18 month period I suppose. Always replace filters every 6 months and disinfect the system at filter changes.
You can check for chlorine breakthru with a low range chlorine test kit too.

[platax88]

How do you dissinfect the system?

I am going to buy a complete new set of filters. you think i am ok
WITH THIS KIT?

Thanks for all your help AZDesertRat!

[Buckeye Hydro]

Originally posted by platax88
I have been going through tons of di resin lately. So i tested the water coming out or the ro membrane (before going into DI).

Here are the numbers:

Tap = 278ppm

After RO membrane = 172ppm

After DI = 0 ppm

It seems to me that the ro membrane is faulty, because it should be removing 99.9% correct? This was replaced about a year ago. Don't know why it would have become damaged. Any ideas?

Your membrane might be shot, or it might just not be installed correctly.

Line up about 8 identical drinking water glasses in fron of your system. With your DI water tube in one hand, and the RO waste water tube in another, in ht etime it takes to fill one glass with DI water, how many glasses do you fill with waste water?

You'll not see the RO membrane remove 99.9% of the TDS in the feed water. Something better than 90% is a reasonable expectation, and if you have a high rejection membrane, you should be seeing something higher than 95% (or better). Your DI resin is intended to remove the remaining TDS.

Russ

[Buckeye Hydro]

We recommend sanitizing your RO/DI system at least once per year. Schedule this process at a time when you are planning to replace your cartridges. These instructions apply to water purification systems without a pressure tank. Before you begin assure that you have about an hour available, and that your work area and hands are clean.

Turn off the water supply to the system.

Remove all housings and remove all pre-filters and post-filters from the system including sediment filters, carbon filters, in-line filters, and deionization cartridges. Remove the reverse osmosis membrane(s).

Wash housings with a soft brush or cloth in warm soapy water. Rinse thoroughly to remove all soap. Don’t forget to carefully remove and wash all o-rings. Lubricate the o-rings with a small amount of silicone grease and reinstall them.

Fill each of the first two prefilter housings with one cup of potable water and two tablespoons of plain, unscented household bleach. With this sanitizing liquid still in the housings, screw them back on to the system.

Turn on the water supply a bit, allow water to fill the entire system, and assure water is flowing out of the waste line and the purified water line. Place the outlet of the drain tube and purified water tube slightly higher than the system to assure these tubes are full of the sanitizing solution. When the sanitizing solution has reached the outlet of each tube, and with the outlet of each tube placed above the rest of the system, shut off the water supply for 30 minutes.

After 30 minutes, turn the water supply on and assure that water exits the system from both the drain tube and the purified water port. Flush the sanitizing solution from the system for 5 to 10 minutes, or until the strong odor of chlorine can no longer be detected.

Turn off the water supply and install new filters, taking care to flush the filters as appropriate.

We recommend keeping a maintenance record for your system. Record the date of the sanitizing and filter replacement.

Russ

[NaClH20reeffish]

Good info on sanitizing!

[platax88]

Russ --

Thanks so much for taking the time to explain the process. have new filters on order and i will do this when i get them.

[Buckeye Hydro]

You're welcome.