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View Full Version : Time to change RO/DI filters?


dtaranath
09/26/2006, 12:40 PM
Raw water: 316ppm
RO only: 096ppm
RO/DI: 006ppm


I'm using Typhoon III. Is it time for me to change filters? I've only been using it since early July. I use DI Bypass and Fast Flush before every use. It's made about 300-400 gallons so far.

If I have to change filters, do I have to change all of them? Or just the DI resin?

cybertec69
09/26/2006, 01:34 PM
time for some resin change "looks to be exuasted", the other filters should be fine, maybe the sediment filter also, see how it looks, if it is brown, change it also, my Raw waters PPM is 34-35, wow you have some high PPM city water.

dtaranath
09/26/2006, 08:06 PM
ah, thanks. the sediment filter is getting brown, but still some areas of white can be seen. Should I still change it?

AZDesertRat
09/26/2006, 08:32 PM
You need to review those numbers again. Do you mean the RO only is 9.6 or 96? If its 96 you have big problems, you should only be seeing about 6 or 7 from the RO only. At that rate your DI should last about 300 to 400 gallons before you start to see an rise in TDS above 1 or 2. I would recheck the RO again using a squeaky clean water glass and triple rinse it in DI before and after use. If you are sending out a RO only TDS of 96 you will only get about 32 gallons out of a new DI cartridge.

Sediment and carbon fliters should be changed every 6 months unless you have really high sediment then it may need them more often than that. RO membranes should last 3+ years and DI should treat approx 3000 total TDS, so if your RO output is 9.6 TDS you would get 312.5 gallons of good water per DI. The DI is not a scientific formula but its darn close based on bench and field testing results.

BTW, the average TDS nationwide is about 250 so your water is not that bad. Mine is 735 TDS.

Thefilterguys
09/27/2006, 10:36 AM
Your readings are unclear but without a doubt your DI resin looks to be exhausted once you start to see a TDS reading it time to change. With a RO reading of 10 and you are running a stright DI cartridge you should get about 600 gallons of production water if it is a layered silica/DI you will only get 400. Everyones municipal water veries so production can also be higher or lower which may account for the difference between AZ and I. Your sediment and carbons should still be good after three months.

Jim

crumbletop
09/27/2006, 10:49 AM
<a href=showthread.php?s=&postid=8228353#post8228353 target=_blank>Originally posted</a> by AZDesertRat
You need to review those numbers again. Do you mean the RO only is 9.6 or 96? If its 96 you have big problems, you should only be seeing about 6 or 7 from the RO only.

Yeah, recheck those numbers. Have the post RO numbers always been like that? If the numbers are accurate, I'd contact Walter at AWI as you have an issue with your membrane. He may be able to send you a replacement and some replacement DI resin, as this shouldn't happen in a new unit.

Thefilterguys
09/27/2006, 12:15 PM
crumbletop I'm betting on his readings are the problem not his membrane. If the RO reading is 9 and he has a 75 GPD membrane that would be a 97% rejection rate. If the RO reading was 96 his DI production water reading would also be sky high after 60-70 gallons of production water.

Jim

dtaranath
09/27/2006, 09:43 PM
well, the RO was definitely 96. I'll recheck it again with a squeaky clean glass. also, i have a 75gpd membrane.

Thefilterguys
09/27/2006, 11:27 PM
Well then I guess I was wrong in assuming sounds like your membrane is toast and you need to contact AWI.

Jim