RO Filters Question

[ffc3]

I've got a Kenmore RO filter that's reaching its one year mark in September so I ordered and received a new one and inline TDS meter from Bulkreefsupply. I didn't have a TDS meter before so I tried it on the old system. It reads 113 tap water, 7 RO water and 0 after DI so I'm thinking about using it until the RO reads a little higher. My question is that the carbon/sediment filters are reaching 6 months old in September also and I do not want to buy replacements for them so is it safe to keep using the old system until the TDS reads higher? I'm not sure if the RO membrane will filter out chlorine and other chemicals that a 6 month+ carbon prefilter misses, or should I just install the new system? Thanks.

[HowardW]

The pre filters (sediment and carbon) have no real effect on your TDS and their job is to remove sediment and chlorine / chloramines before they can reach the membrane.

[AZDesertRat]

The prefilter and carbon should be changed at 6 months intervals especially if you use the unit for drinking water too.
Did you get the correct RO membrane? Most Sears units do not use a standard TW1812-xx membrane but use the 1810 series instead which are different and harder to find. The 1812 will not seal in a 1810 housings, the o-rings and seal are different.

[ffc3]

After reading my post I can see where I messed up and it is confusing. I meant I already bought a whole new 4 stage RO system from bulkreefsupply. Since I found out the TDS is still low on my old system, I was wondering how long I can keep using it without replacing the prefilters,even though the prefilters are 6 months old.

[AZDesertRat]

There are two dangers involved with going past the recommended 6 month intervals. One is the increased risk of bacetrial or virial growth inside the filters and housings. Another is exhausting the carbon and melting the membrane with chlorine that gets through.
6 months is just a guideline but its an easy to remember time interval and history shows the filters are ready about then. I extend past 6 months but I use 0.2 micron absolute rated prefilters that trap bacteria and viruses and I also use a low range chlorine test kit to monitor for chlorine breakthru.