What do your RO/DI filters look like when they need to be changed?
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redfishbluefish
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First off, the only filter that will show color change over time will be your first filter...the sediment filter. I would not base changing this on color. I would consider the amount of water you make and the quality of incoming water. My imcoming water is from a public water system with less than 200 disolved solids, and I make about 25 gallons a week. I change my sediment and carbon blocks once a year. And, my sediment filter looks like chocolate milk.
DFW
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I make about 1200 gallons a year, and the sediment filter looks light brown. I change sediment, and 2 carbon block filters once each year. TDS out of the tap runs about 160 ppm. Of course when you make 1200 gallons of usable water, about another 4000 gallons, or so, have gone through the filters.
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Unless you have iron, manganese, sediment, silt, particulate or colloidal material problems they should not look much if any different than when they are installed. And redfish is correct, the only filter that should show any difference is the sediment filter. If you are seeing color differences or a build up on your carbon block then your sediment filter is too coarse and passing solids through to the carbon which is bad since it plugs the carbon pores rendering it useless for chlorine adsorption.
Use a pressure gauge or better yet two pressure gauges to monitor the before and after pressure across the sediment and carbon and change them when you see much of a headloss. Lower pressure available to the membrane means it will not be as efficient and your DI will not last as long. I have a gauge on the tap water side and on the membrane housing so I can see pressure drop at a glance. My TDS is between 550 and 600 and I can easily get a year to 18 months out of a 0.2 micron absolute rated sediment filter with no appreciable color change since our iron, manganese and suspended solids are very low. And thats only a 2-3 psi drop at most before changing.
Use a pressure gauge or better yet two pressure gauges to monitor the before and after pressure across the sediment and carbon and change them when you see much of a headloss. Lower pressure available to the membrane means it will not be as efficient and your DI will not last as long. I have a gauge on the tap water side and on the membrane housing so I can see pressure drop at a glance. My TDS is between 550 and 600 and I can easily get a year to 18 months out of a 0.2 micron absolute rated sediment filter with no appreciable color change since our iron, manganese and suspended solids are very low. And thats only a 2-3 psi drop at most before changing.
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143MPCo
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Lady's and Gentlemen,
I don't think he was asking for a visual representation as a sign of when a filter needs to be changed, more like "when they need to be changed" what do they look like...
IMO, gauging a filters change interval on visual dirtiness is not what he was after...
I don't think he was asking for a visual representation as a sign of when a filter needs to be changed, more like "when they need to be changed" what do they look like...
IMO, gauging a filters change interval on visual dirtiness is not what he was after...
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Fishinwall
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Thanks. I was wondering if there was a visible sign on the sediment filter. I figured that's why they are in clear canisters.
All good info though. It would be nice if when someone says roughly how long their filters last to mention the size of their tank and frequency and size of water changes.
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Not that I know of... But, clearly seeing the junk in the stage one filter can be an indicator of a mishap like a water main break or something to that accord.
You have a lot of variables around this one... everyone's tank needs are different so no clear cut answer, you need to take into consideration the size of tank, husbandry, tank ventilation (or lack of), evaporation, how often you back-flush, etc. all boiling down to how much RO/DI water you will need, thus how long the filters last. That will all play a part, not to mention how clean or dirty the source water is... from the posts above everyone's TDS is different, In my area, MDC sits me at 55ppm TDS (source water)...
I have seen ppl using well (source water) water and that sat at 25ppm... so it has to be based on your situation, how clean the water is, and a few other factors.
I go by the rule that if the filter/s clogged (drop in pressure gauges) replace them, if my final stage TDS meter is reading higher then 8-10ppm TDS on the incoming side of the DI canister, replace all the pre-filers.
The one "visible" sign would have to be with DI resin, more specifically the type that changes color as it's used up.
Again, it will be different for each person and their individual/s requirements.
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We suggest changing your sediment and carbon after 2500 gallons of water passes through these filters. Many systems are set up with approx. 4 gallons of waste water for every gallon of product water you get. This being said, suggested to change them approximately every 500 gallons of product water.
There are factors that can lengthen this: water softener, water quality, etc.
However, I prefer to change these filters more frequently compared to changing the membrane more frequently. Mainly because the sediment and carbon (maybe $15) are cheaper than the membrane(approx. $45). By not changing them enough, the membrane can get clogged with sediment because the sediment filter is to clogged to get it all or fried by chlorine if the carbon is not changed.
There are factors that can lengthen this: water softener, water quality, etc.
However, I prefer to change these filters more frequently compared to changing the membrane more frequently. Mainly because the sediment and carbon (maybe $15) are cheaper than the membrane(approx. $45). By not changing them enough, the membrane can get clogged with sediment because the sediment filter is to clogged to get it all or fried by chlorine if the carbon is not changed.
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Fishinwall
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The sole purpose of the sediment and carbon block filters is to protect the RO membrane which does 90-98% of the treatment so staying up with them and doing the annual disinfection are wise choices.
If you do find significant discoloration or a build up on the sediment filter then it may need replacing more often than the 6 month intervals suggested by almost every legitimate RO vendor as at that point you are probably seeing a noticeable drop in pressure which reduces the efficiency of the RO membrane meaning your DI life will also be shortened. The sediment filter is relatively inexpensive and protects the billions of tiny microscopic pores in the carbon block so it can do its job of adsorbing chlorine and organics. Sometimes when using high quality, low micron sediment filters and low micron extruded carbon blocks you can replace just the sediment when it gets dirty and get the full life of 10-20,000 gallons out of the carbon as long as it remains protected. In this case, which is what I do myself, in addition to the two pressure gauges to monitor headloss due to plugging sediment filters I also use a low range chlorine test kit to monitor for chlorine break thru indicating the carbon is exhausted.
What most people find is a 6 month interval marked on a calendar or even on the RO units bracket or wall with a sharpie is much easier to remember.Its $15-$25 well spent and could make a membrane last 10+ years which is a big operational cost savings.
The absolute best thing you can do for an RO membrane though is a water softener. Membranes love soft water since it does much of the work for them by removing the calcium which scales them up over time.
If you do find significant discoloration or a build up on the sediment filter then it may need replacing more often than the 6 month intervals suggested by almost every legitimate RO vendor as at that point you are probably seeing a noticeable drop in pressure which reduces the efficiency of the RO membrane meaning your DI life will also be shortened. The sediment filter is relatively inexpensive and protects the billions of tiny microscopic pores in the carbon block so it can do its job of adsorbing chlorine and organics. Sometimes when using high quality, low micron sediment filters and low micron extruded carbon blocks you can replace just the sediment when it gets dirty and get the full life of 10-20,000 gallons out of the carbon as long as it remains protected. In this case, which is what I do myself, in addition to the two pressure gauges to monitor headloss due to plugging sediment filters I also use a low range chlorine test kit to monitor for chlorine break thru indicating the carbon is exhausted.
What most people find is a 6 month interval marked on a calendar or even on the RO units bracket or wall with a sharpie is much easier to remember.Its $15-$25 well spent and could make a membrane last 10+ years which is a big operational cost savings.
The absolute best thing you can do for an RO membrane though is a water softener. Membranes love soft water since it does much of the work for them by removing the calcium which scales them up over time.
What ever AZ says when it comes to water I listen to. So whatever be said.
Spectrapure sells a small, inexpensive, low range chlorine test kit.
https://www.reef2reef.com/forums/eq...filtration/170914-ro-de-ionization-break.html
You can do it with just one gauge but its a little harder. What I would do is turn the system on then kink, valve or plug both the treated and the waste lines so nothing is running and see what the static or non-flowing pressure is. Write that down somewhere so you can refer to it. Now open the lines back up and see what the flowing pressure is and note if there is any drop between static and flowing. If it is much more than a couple pounds your filters are probably plugging or fouling and in need of replacement. Do this when new filters have been installed then again monthly or so to see how much the pressure drops with time. Don't let it go too much though as lower pressure means a less efficient RO membrane so you will be replacing DI more often and the membrane will not last as long and both are more expensive than sedimen tand carbon block filters.
https://www.reef2reef.com/forums/eq...filtration/170914-ro-de-ionization-break.html
You can do it with just one gauge but its a little harder. What I would do is turn the system on then kink, valve or plug both the treated and the waste lines so nothing is running and see what the static or non-flowing pressure is. Write that down somewhere so you can refer to it. Now open the lines back up and see what the flowing pressure is and note if there is any drop between static and flowing. If it is much more than a couple pounds your filters are probably plugging or fouling and in need of replacement. Do this when new filters have been installed then again monthly or so to see how much the pressure drops with time. Don't let it go too much though as lower pressure means a less efficient RO membrane so you will be replacing DI more often and the membrane will not last as long and both are more expensive than sedimen tand carbon block filters.
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Fishinwall
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My pressure gage when flowing is always between 46 and 56... It fluctuates. In the green area.
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