TDS Reading 005ppm and Testing positive for Chlorine?

floridareef · Nov 6, 2011

I just changed my sediment and carbon filters and filled my top off container and happened to smell chlorine. I tested for CL with a walmart pool test kit and the ro water is as yellow as the color chart shows. How could this be with a tds reading of only 5ppm?. With that much CL I would think the tds reading would be much higher.

Thanks for any input.....

AZDesertRat · Nov 6, 2011

Drinking water normally contains 0.5 to 2.0 ppm residual chlorine so you are seeing 5 ppm TDS so thats close.

What did you change exactly? Did you disinfect and rinse the housings before installing the new filters? How old is the RO membrane? What micron size are the filters you installed? What is your tap water TDS, RO TDS and RO/DI TDS if you have DI? What is your waste ratio? How often do you change filters and do you use high quality replacements?

Where did you draw the TDS samples, directly from the filter or from storage? Did you rinse the chlorine test kit well with RO/DI or distilled water to remove any trace residuals?

Rogger Castells · Nov 6, 2011

what type of filter do you have?

floridareef · Nov 6, 2011

I changed the sediment and carbon, the membrane is 7mths old. 1 micron sediment, filters are from the filter guys. Tap water 260ppm Ro reading 005, not running a DI. I change the filters when my ro tds reads 15ppm or higher. TDS samples drawn from the filter. Everything rinsed and cleaned befor testing and filter replacement.

I dont understand why a new carbon filter would let any chlorine pass through. I checked and I didnt leave an old gasket in the carbon canister, I dont know whats going on?

AZDesertRat said:
Drinking water normally contains 0.5 to 2.0 ppm residual chlorine so you are seeing 5 ppm TDS so thats close.

What did you change exactly? Did you disinfect and rinse the housings before installing the new filters? How old is the RO membrane? What micron size are the filters you installed? What is your tap water TDS, RO TDS and RO/DI TDS if you have DI? What is your waste ratio? How often do you change filters and do you use high quality replacements?

Where did you draw the TDS samples, directly from the filter or from storage? Did you rinse the chlorine test kit well with RO/DI or distilled water to remove any trace residuals?

floridareef · Nov 6, 2011

Rogger Castells said:
what type of filter do you have?

Its a unit from the Filter Guys about 5 years old.

AZDesertRat · Nov 7, 2011

If you have chlorine present the water is bypassing the carbon block somehow. Look at the gaskets on the carbon block and make sure they are centered on the filter then look for indentations where the canister and lid grip them. If you don't see indentations in the rubber gaskets try peeling the gasket off an old filter and doubling them up on one end to stop the bypass. They should be centered in the gasket not shifted to one side. You will want to cure this quickly as chlorine will melt a membrane in a hurry.

Sediment filters and carbon blocks have very little to absolutely noting to do with TDS so yoou cannot go by final TDS for swapping them out. The RO membrane does the TDS removal in your case and a DI would do the final 2 to 10% if you had that. The sediment and carbon remove suspended solids, big stuff in the visible down to 1 or 5 micron range depending on your filters, an of course chlorine. The RO membrane removes TDS or dissolved solids, things in the 0.0001 micron range, a thousand times smaller that the sediment and carbon filters can possible trap.

You change the sediment and carbon block every 6 months like clockwork period, regardless of TDS. You change the membrane when the rejection rate falls off top say 96% or whatever you think you can live with.