Slime in RO unit?

[King-Kong]

Has anyone ever experienced a slime/bacteria infultrating their RO/DI machines?

When I last changed my prefilters due to my DI resin getting exhausted too quickly, I discovered slime on these filters. It was whitish/clear, and was mostly on the rubber gaskets.

I am experiencing some very very odd issues with my RO machine and wondering if this could be the reason.

[AZDesertRat]

Yes, it is normally from lack of maintenance, not disinfecting the housings and/or exposure to heat, light and temperature extremes.
Completely disassemble the unit including the membrane and disinfect the entire system with bleach before reassembling with new filters. Check the membrane closely to see if it is contaminated too. I have seen where people disinfect the membrane with peroxide but have no experience with it myself.

[King-Kong]

Have you heard of it causing DI refillable cartridges to become exhausted faster than normal?

Right now, my RO is outputting 18ppm (100gpd), and my DI cartridge, which used to last 6mo-8mo, is now lasting one month. I also changed my prefilters.

[AZDesertRat]

I would say its possible. I would disassemble the unit clean and disinfect it and try again. DI resin is hard to predict the life of in some cases. How old is the bulk resin, was it stored damp in a vacuum sealed bag? If not it greatly shortens the DI life and can kill it completely. Good quality resin has a capacity of about 2000 total TDS per 16 oz of resin when it is fresh so you can gauge pretty closely how much water you can expect if you know your RO output TDS and how much water you make. If you are sending out an RO TDS of 18 you should get about 111 gallons per pound of resin. If you have a standard sixed vertical canister it holds up to 24 oz if packed correctly, horizontal tubes hold between 6 and 16 oz in almost all cases.

[King-Kong]

Well, your numbers concern me, because, well, I estimate I use about 3 gallons a day (I evaporate a lot, and I do 5 gallon water changes a week). 111 gallons, then, lasts a little over a month, and that's about how long the resin has been lasting.

Could all of this be much to do about nothing? My membrane used to output like 3-5 tds when it was new. So is that why my resin lasted so much longer the first time?

Is it time for me to decide between a new membrane, or keep funneling new DI in? Should I go down to a 75gpd membrane to save resin, longer?

[King-Kong]

Also, the resin came in a ziplock bag, slightly moist, air removed, and it came from a very reputable ro/di company that has served me with incredible customer service. So, I would assume the DI is at least of modestly well quality.

[AZDesertRat]

Absolutely get a 75 GPD RO membrane, 100 GPD membranes are not as efficient, in some cases 90% vs 98% for the 75. If you were getting 3 to 5 TDS out of a 100 GPD thats pretty amazing. If the resin was packaged like that it should be good for a couple of months if kept sealed, if it is allowed to dry out once opened it goes bad quickly. I prefer vacuum sealing as it will keep about 6 months that way.

[bevis28]

Originally posted by King-Kong
Have you heard of it causing DI refillable cartridges to become exhausted faster than normal?

Right now, my RO is outputting 18ppm (100gpd), and my DI cartridge, which used to last 6mo-8mo, is now lasting one month. I also changed my prefilters.

18PPM ? ? ? mine is ZERO at the DI output...

1. what is the input supply water TDS PPM ?

2. what is the RO Only TDS PPM ? ( if you have access to the
output of the RO membrane )

3. are you using a filmtec RO membrane ?

4. are you using neuclear grade DI resin ?

[bevis28]

Originally posted by King-Kong
Well, your numbers concern me, because, well, I estimate I use about 3 gallons a day (I evaporate a lot, and I do 5 gallon water changes a week). 111 gallons, then, lasts a little over a month, and that's about how long the resin has been lasting.

Could all of this be much to do about nothing? My membrane used to output like 3-5 tds when it was new. So is that why my resin lasted so much longer the first time?

Is it time for me to decide between a new membrane, or keep funneling new DI in? Should I go down to a 75gpd membrane to save resin, longer?

there is a difference between the RO output TDS and the DI output TDS. i assume that you are going thru a sediment filter and then a carbon block and then to the RO membrane and finally to the DI stage which will strip the phosphates and silicates that the RO would not. thats why im asking for a RO output TDS and a DI output TDS. 1 month on the DI resin is rediculous unless you are purifying sewage water.

[King-Kong]

Tap 180, RO only 18, after a fresh di packing of di; 0. After a month, the DI TDS begins to creep up fast, eventually putting bad stuff back in.

pre filters before were; sediment, 10 micron carbon block, 5 micron carbon block. Then after working with ro/di company, they feared ammonia nuking DI, so they sent me (free, btw), new 10/5/1 micron carbon blockprefilters. Didn't really help.

I checked for ammonia last night (as they instructed); using an aquarium pharm. test kit (cheap, but brand new, purchased for this purpose), I had issues detecting any ammonia in my tap, let a lone any ammonia in the post-RO/pre-DI. I dont know how much ammonia is harmful, but the test's first unit of measure is .25ppm, and I cant say I saw it go past 0ppm.

Every filter has been changed except for the membrane, and the only "odd" thing ive found is the slime. Pressure is also fine into the unit, and output speed seems consistant with previous performance.

..and yes, FilmTec membranes.

[jdieck]

Your membrane rejection is 90% which is within the specifications for a 100 gpd membrane.
Ammonia may not be present in the tap but may be present after the carbon filters if your tap water is treated with chloramines instead of chlorine. Chloramines are broken apart by the carbon one of the results of the reaction is Ammonia.
I fyou switch your membrane to a 75 gpd which has a rejection of 98% or better your RO output TDS with 180ppm at the inlet will be around 2 to 4 ppm so your DI cartridge shall last six times longer.

[King-Kong]

jdieck; I did not detect any ammonia after the prefilters carbon blocks/RO.

[jdieck]

So there is none and your tap is not trated with chloramines... Lucky you

By the way, another thing that consumes the DI cartridge even faster than high TDS from the RO is high level of dissolved CO2 in the inlet water.

[King-Kong]

Well, no ammonia according to this test kit I picked up at petsmart, that uses units of .25 ppm -- I dont know what a harmful level would be, but that cheap test kit didnt show any (but the test kit could be wrong / not high enough resolution)

Could the bacteria/slime be a creator of co2?

[AZDesertRat]

Call your water utility and ask if they use chloramines for residual disinfection. Its really not that common in the US but is being used more and more as drinking water regulations get stricter.

[sixliner6]

AZ could you giva detailed instruction on how to disinfect an RO/DI system?

[AZDesertRat]

I just did earlier this evening on another thread. Try doing a search of my user name as I don't remember which thread it was in.

[Buckeye Hydro]

We recommend sanitizing your RO/DI system approximately 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 vertical housing with one cup of potable water and three to four tablespoons of household bleach, and 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.

Turn off the water supply and install new filters.

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

[AZDesertRat]

Thanks Russ.

[BeanAnimal]

King Kong... you say your unit is from a reputable dealer and your resin should therefore be good. But your rejection rate (90%) is that of a 100GPD membrane... most of the "reputable" dealers I know would not sell you a 100 GPD membrane and would instead recomend a unit with a DOW filmtect 98% rejection membrane. That includes RUSS at Buckeye, Bryan at PurelyH20, Filterguys.biz, Spectraprure and AWI. So i somewhat question the "reputable" part with regards to good advice and that then brings into question the source of their components.

Of course if you wanted the 100GPD membrane, then a reputable dealer would have explained the difference between it and the 75 GPD filmtec with regards to rejection and DI life.

Bean

[King-Kong]

Originally posted by BeanAnimal
King Kong... you say your unit is from a reputable dealer and your resin should therefore be good. But your rejection rate (90%) is that of a 100GPD membrane... most of the "reputable" dealers I know would not sell you a 100 GPD membrane and would instead recomend a unit with a DOW filmtect 98% rejection membrane. That includes RUSS at Buckeye, Bryan at PurelyH20, Filterguys.biz, Spectraprure and AWI. So i somewhat question the "reputable" part with regards to good advice and that then brings into question the source of their components.

Of course if you wanted the 100GPD membrane, then a reputable dealer would have explained the difference between it and the 75 GPD filmtec with regards to rejection and DI life.

Bean

My dealer suggested the 75gpd unit. I was told to go 100gpd by melev, a very long time ago.

[BeanAnimal]

Doh! you would have been better off witha filmtec 75GPD. In any case... back to the regularly scheduled programming.

Bean