Ro/di tds?

I have the brs 4 stage ro/di filter and have been running it for about a year now. Have a handheld meter that I usually check the batch water with and it is usually 0, until now. Last week it was at 5 this week 15-20 . I have already ordered their replacement kit which includes sediment filter, carbon , and di resin refill... Oh, and also ordered an ro membrane flush kit from them. Tds of my tap water is around 480.

My question is, does this sound about right? Is the kit that I ordered enough? Is the tds of 14-20 with worn out di resin indication of the need for a new ro membrane? Or is that about right?

 

Measure the tds after the membrane. If you haven't changed the filters in 2 years your probably due for a new membrane. Prefilters should be changed every 6 months.

please excuse wrong words, I posted this from my phone that auto "corrects."

 

It's only been 1 year maybe a little less and I just realized I should have changed the pre filters at 6 months.

 

Probably will be OK, I did the same on my unit, replaced the prefilters and it has been fine.

 

Tds after ro membrane = 12

Tds after di = 21

Tds from tap = 394

Do you think my ro membrane is fine if I flush it with the flush kit from brs and then replace the sediment, carbon and di ?


Thanks for the help...

 

Thanks 2in10, that's what I'm hoping.. I usually research everything thoroughly but for some reason I was under the impression that as long ad it read 0 tds I was fine but now that I'm researching, I see that regardless the pre filters should have been changed after no longer than 6 months to reduce wear on the membrane!

 

Also, from the numbers I posted above, it seems that after the ro that would be about a 97% rejection rate? Is that within spec? Keep in mind, this is still with the old pre filters as the new ones won't arrive till Monday.

 

Prefilters and carbon should be replaced every 6 months like clockwork and disinfect the system while you have it down, it only takes a few minutes.
Prefilters and carbons have very little to absolutely nothing to do with final TDS, their job is to protect the RO membrane from chorine and suspended solids (TSS, big particles like sediment, particulates and colloidal materials) not TDS which is dissolved solids and the job of the membrane and DI resin.
97% is common for a 75 GPD Dow membrane, most are around that when new.

Keep up with the 6 month replacements and monitor your RO only TDS more often, this, along with a dropping GPD is what will tell you when your membrane is failing.

Forget the flush kit, they have no proven value other than to lighten your wallet and give you a warm fuzzy feeling. All the flushing a membrane needs is to keep the waste ratio at the recommended 4:1. This is a continous flush while the unit is in operation and necessary to keep the membrane fresh.

I am surprised your DI made it a year without replacement with a TDS of 12 going in, you must not make much water and you probably do not have CO2 in your water. I found when my RO TDS was 12-15 I could only get about 150 gallons of 0 TDS RO/DI water before it needed replacing no matter what normal mixed bed resin I tried.

 

Should be ok after you replace the filters. Like AZDesertRat said replace those prefilters. When he says disinfect you just put a few drops of bleach in each canister without the filters and turn the ro on just long enough to fill it with water, then let it sit for an hour with the water off, then turn the water back on to flush out all the bleach. Never buy a membrane flush kit. I didn't even know they had one. The membrane is always flushing, that's what the reject flow is. If you can bypass your capillary tube open it and that will flush larger particles from the membrane.

 

Here are my disinfection directions from a previous thread.

All vendors should provide disinfection directions with a new unit. I would check with your vendor. Basically it involves removing the prefilter and carbon(s), adding two tablespoons of regular unscented bleach, reinstall the empty housings, disconnect the line from the carbon up to the RO membrane so you don't get any bleach on the membrane then opening up the water supply to fil the housings. Let it sit about 5 minutes then open the supply again and flush it out until all smell of chlorine is gone.
When installing new the new filters after disinfection, or any replacements, flush the filters one at a time to remove all traces of antimicrobial treatments, glues, binders and carbon dust. Install only the prefilter first and flush it out the line you previously removed from the RO membrane. Next install the carbon and do the same flush. If you have two carbons then install the second one and do a flush before hooking back to the RO membrane. These steps will all extend the life of your membrane.