RO Filter Questions

[skp]

Hi i have a 100 GPD RO filter.

It came with a 0.5 micron carbon block and a 5 micron sediment.

It has only been used 3 months but I couldnt help want to try a smaller micron sediment filter so i purchased a 1 micron sediment filter.

I decided to just replace the carbon block as well and i bought a carbon block filter thinking it was the same but it is actually 5 microns and not 0.5 microns.

I replaced both the sediment and carbon anyways and then let it run with the valve open bypassing the ro membrane for 10 minutes. Then i closed the valve and made a 5 gallon bucket of water and then a 1.25 gallon jug of drinking water. I tasted the drinking water and it tastes like tap water! I can taste the chlorine.

Am i being paranoid? The chlorine shouldnt pass through the ro membrane even if it did pass through the carbon block right? I can definitely taste something for sure though.

Also i can now see a few brown stains on my carbon block and my sediment filter is clean white.

Is this all normal? I dont have access right now to a tds meter.

 

thanks

[AZDesertRat]

The only way to tell if chlorine is passing through is with a low range chlorine test kit, you might see it with a good pol test kit too but probably not.

 

The 0.5 micron carbon block is good for 20,000 gallons of normally chlorinated water, the 5 micron is probably good for 3,000 to 6,000 gallons depending on the quality of the filter. Now keep in mind that is total gallons so its the waste as well as the treated water so with a normal 4:1 waste ratio thats 4,000 gallons of RO or RO/DI and 16,000 gallons of waste with the 0.5 and only 600 to 1,200 gallons of RO or RO/DI and 2,400 to 4,800 gallons of waste with the 5 micron. Big difference. The 0.5 micron is also highly effective on the chlorine portion of chloramines while the 5 micron not so much.

 

Granted you have not made much water but you should still not be seeing any chlorine in the finished water. Free chlorine will melt a TFC membrane very quickly so you want to get this solved soon. I would also get your hands on a handheld TDS meter, I cannot imagine owning a RO system without a TDS meter, they need to be monitored and thats the best way to do it.

 

You really want a prefilter the same micron rating or even smaller if possible so it protects the billions of tiny pores in the carbon block so it can do its job of adsorbing chlorine and VOCs. If the prefilte ris larger it is passing colloidal materials and silt on to the carbon making it act as a secondary sediment or particulate filter and rendering it useless for chlorine. I use either a 0.2 or 0.5 micron absolute rated prefilter and a 0.5 micron chlorine guzzler type carbon block and they work tremendously in my 600+ TDS tap water.

 

Hopefully your 100GPD membrane is a GE or Applied and not a Dow Filmtec as the first two are 96-98% efficient and the Dow is only 90% efficient, its not really an RO filte rat all but is considered a nano filter which is not even approved by the NSF for drinking water. The GE and Applied are really identical to the Dow Filmtec 75 GPD which is a 96-98% membrane and is approved by NSF. The difference is really apparent when using DI as the resin exhausts much quicker with the one versus the others.

[skp]

Thanks for all the info.

I cant seem to find a carbon block smaller than 5 microns arround where i live.

Im thinking of putting my old one back in.

is it ok that it was out and dried off?

Do you think bacteria grew on it?

 

edit:

also.. i just tried some filtered water that i left out over night and the taste is still there so i dont think that its chlorine. There's no chloramine in our tap water.

and since i changed my carbon block the pressure has risen by 10 psi.

this filter, brand new, was measuring 63-66 psi

[AZDesertRat]

Your original carbon should have lots of life in it still. It does not hurt for the prefilter or carbon to dry out if they have been kept clean, its the membrane and resin that must stay wetted once in use or they go bad quickly.

[skp]

is it normal that there are orangish brown stains on my new carbon?

I think it came like that brand new

[AZDesertRat]

I sometimes see that too, its normal but I cannot explain it.