RO/DI Filter Life

Tango2 · Jul 25, 2016

Just curious what type of filter life you typically get out of your RO/DI filters.

My original setup was typically run manually filling a 10 gallon container about every other week. My DI resin lasted over 2 years, and I started to see very low TDS in my output water.

I then replaced my aqualifter with a peristaltic ATO and put float valves on my ATO. Although I try to shut the water valve off manually when the containers are full and only use the float valve as a shutoff, I definitely forget at times. I've noticed my DI resin is 75% orange in about 8 months of use. TDS is still 0 coming out.

Is this probably from the frequent cycling of the filter? I do know the RO water output has pretty high TDS for the first few minutes of production.

How often do you replace your carbon/sediment filters?

Rob Lion · Jul 25, 2016

I create 60 litres (13 gallons?) of RODI water a week for a 10% water change and ATO for my 250L tank.
I only run my RODI unit at 0 TDS, so as soon as it shows anything above zero I swap out the resin, usually every 6 months, and I change the carbon and pre filter cartridges then too.
In the year that Iv'e had my unit, i've never needed to change the membrane, I always back flush the membrane before and after use too.

Tango2 · Jul 26, 2016

From what I recall, that seems excessive to change the resin. I've recently installed an inline TDS meter with two sensors. I was really surprised how long it took for my RO water to reach the optimal output (a TDS reading of about 3). While I didn't time it, I just got new containers (78 Gallon) to replace my small 10 Gallon ones. My RO/DI ran about 24 hours to fill the container, and after 5 minutes or so my RO output was reading 3, and my DI output was at 0 TDS. The RO reading started off at about 35 and slowly crept down to 3.

My thoughts are that if my RO/DI unit was working off of the float valve in my reservoir, it would never run for 5 minutes to get that "optimal" output. In theory, this would cause relatively high TDS water to pass through the DI resin, drastically shortening the life of the resin. Does this make sense?

I have a fast flush feature on my RO/DI, but as often as I had to refill my containers, I admit I didn't use it much. I will be filling another 78 gallon container in the next few days, I may try to do a couple tests on that one.

Buckeye Hydro · Oct 3, 2016

The frequency of prefilter (prefilter = any filter prior to the membrane) varies.

We have lots of customers on well water, and many of them have lots of sediment in the water. Many people on municipal water have very little sediment in their tap water.

Make sure you understand the chlorine capacity of your carbon block. We typically recommend you not go beyond about half of that capacity, or about 6 months, whichever comes first.

Russ

cromag27 · Oct 3, 2016

Sediment and carbon is usually six months. di replaced once you see 1 tds. membrane can last a few years. flushing your unit before and after making water can help extend the life of the filters and membrane.