Replacing Filters

My TDS meter popped up with a 1 ppm at the end of my weekly water for change. Ordered the complete set of filters, including a new membrane. Question is - do I need to replace everything? Seems like I should get more that 4.5 months from the filters.

Anyone have advise on this subject?

 

well all filters besides the membrane are fairly inexpensive but I wouldn't change it just yet just change out the carbon and micro filters for now and retest

 

Most filters will last about 6 month depending on the original water parameters, the membrane should last at least a year or more if the filters are maintained.

 

I have very hard water I replace the first stage filter every other month. the sacond on the fourth month and the third every 6 mo. The membrain is every year. If I do less then this The tank it a mess. I would not do less then this. I have found inexpensive filters the make this work so its a walk in the park.

 

I'm no expert as I started using my own ro/di just a few months ago,but with a tds reading of 1ppm in the final product I would think that new DI resin/cartridge should suffice.

 

Thanks!!

Thanks everyone for your input. Based on the information, I can save myself - or at least postpone - the price of the Membrane ($42). It looks like the most expensive of the other three cartridges is the one that needs to be changed, but since the other two are only a third the cost, and they may extend the life of the others, I will replace all three.

 

You did not say whether or not you had a RO/DI system. So, the general rule is; Change the sediment filter when it looks dirty. Change carbon blocks every 6 months if you are producing high volumes of water and every 12 months if you produce low volumes of water. If yo have a DI canister, change it when it changes color. Another indicator is if you notice a drop in water pressure. This could mean the filters are becoming clogged.

 

Thanks for the catch - it's a [FONT=&quot]Puratek 100GPD RO/DI Filter System.
AND It's usage has been:

Initial tank fill - 60 Gallons [12/18]
8 Gallons per week for Top Off and Water change. 20 weeks = 160 Gallons
Misc per week (Cleaning/Rinsing/etc) - ~3 gallons. 20 weeks = 60 Gallons

So - On the first set of filters, I was able to produce only ~280 Gallons. Seems a little low for a 100GPD RO/DI system.:-/


[/FONT]

 

Prefilters and carbons have very little to absolutely no effect on final TDS, they are there to protect the RO membrane.
Change the prefilter and carbon at 6 month intervals and disinfect the system at that time for best perfromance.

Unfortunately you bought a poorly thought out system. "Low Waste" has been tried and dismissed by all the major manufacturers and vendors long ago. It simply does not work as you have evidenced. The RO membrane MUST be flushed with the factory recommended 4:1 waste ratio in order to work as designed. Puratek did not do their research when they built these and they will not be around long. Many complaints such as yours are popping up on all the sites. Think about it, you are accumulating dissolved solids for hundreds of gallons and allowing them to collect on the membrane fabric where they solidify due to their being concentrated. Once they have built up no amount of flushing in the world using tap water will ever remove them short of chemical treatments which is how large commercial membranes operate at low waste.

My suggestion to you is first using a handheld TDS meter get your tap water, RO only before DI and final RO/DI TDS readings, this will tell you the condition of the RO membrane and if it needs replacing or not.
Next buy a normal 4:1 flow restrictor or a capillary tube flow restrictor and trim it for an exact 4:1 waste ratio so the membrane, either new or replacement will stay flushed as required.

Units like these are giving the RO and RO/DI industry a black eye. Not doing their homework and seeing what has already been attempted and failed was a bad move on their part. Talk to GE, the maker of the membrane in the system you have and ask them about the required flushing, or talk to Applied Membranes or Dow Filmtec. They will all tell you it will not work long term, especially in higher TDS waters. All these manufacturers plus the major vendors have tried to invent a better mousetrap for years, if it was really that easy doesn't it kmake sense that people like Air Water & Ice, Spectrapure, PurelyH2O and all the others who have been doing just this for as long as 25 years or more would have units like that?

Sorry you got taken but its not the end of the world and what you have can be made to work and last like it should. I am sure any of the above would be glad to help you reconfigure your system as would many others who can give you lots of sound advice.

 

Thanks DesertRat I really appreciate the information. I'll be looking into the flow restrictor, but it sounds like my membrane is fried.