How often do you change out your filters and membrane? Do you use a flush kit?
RO/DI Filter Changes?
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Mike J.
2500 Club Member
I flush before every fill. I change my sediment filter when it turns brownish and my DI when I get a reading of 1. Both of these things happen about 6 months. I change my carbon filters once a year and my membrane every two years. I guess it depends on how much water you use, too. I use about 120 gallons a month.
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Vanmo92
Community Member
I replace filters every 6months regardless of how they look or TDS. I figure by the time TDS rises damage to the membrae has already been done and its to late. No flush kit but I do bypass the DI for the first 1/2 gallon or so each time after I turn it on because of TDS creep.
Trex
Valuable Member
I usually change out the pre-filter and carbon block around 3-4 months, whenever the production rate starts to slow down.
The current membrane is about 3 years old (( though would have to check my unit to be 100% sure )). I change it and the DI resin whenever my TDS tells me --- the DI whenever I get TDS of 1 or above. The membrane when the TDS raises up above the rejection rate (( 98% for the membranes I use )).
Though, going to start filling my new 210 in the next couple of weeks, so I plan on changing out everything and starting fresh.
The current membrane is about 3 years old (( though would have to check my unit to be 100% sure )). I change it and the DI resin whenever my TDS tells me --- the DI whenever I get TDS of 1 or above. The membrane when the TDS raises up above the rejection rate (( 98% for the membranes I use )).
Though, going to start filling my new 210 in the next couple of weeks, so I plan on changing out everything and starting fresh.
OP
OP
I bought my present filters/membrane on 2/17/14 on average making 60g a month.
Replacing DI resin every 3-4 months, I think-lol.
I recently bought new filters, minus the membrane. Need I be changing them already? Does this sound about right for the amount of water I'm making?
Replacing DI resin every 3-4 months, I think-lol.
I recently bought new filters, minus the membrane. Need I be changing them already? Does this sound about right for the amount of water I'm making?
Trex
Valuable Member
That seems fast.
However, what is the TDS of your tap water?
The TDS post RO, but before the DI resin?
My first di lasted me a year and I make alot of water well for my size tank I do anyways. The second went in 6 months. I just put in the spectrapure super di this round to try it out
knukles55
Active Member
Not trying to hijack the thread but would you guys use any of the cheaper filters off ebay or is there an alternative than paying the high price tag at the fish store...... mind as well just buy a new unit.....
There is no designated time to change your water filters. It's going to depend on the quality of your water, and how much water you make. Also, if you are using a water softener, your membrane and filters will last longer.
We recommend changing your carbon when you change your sediment. Our sediment filter is good for at least 500 gallons of product water.
The DI filter is easy to know when to change. We have color-indicating DI. So as the DI is used it changes from a blue/ black to a rust color. This starts at the bottom and moves up. So you can always tell how much DI resin is left.
Membranes- check your TDS. If you keep on top of your sediment and carbon filters, then the membrane will last longer. A membrane will also last longer when a water softener system is used before the system.
Also, to make your filters and membranes last longer, make more water at a time. For example, don't make a gallon at a time. Make 20 or 40 gallons.
We recommend changing your carbon when you change your sediment. Our sediment filter is good for at least 500 gallons of product water.
The DI filter is easy to know when to change. We have color-indicating DI. So as the DI is used it changes from a blue/ black to a rust color. This starts at the bottom and moves up. So you can always tell how much DI resin is left.
Membranes- check your TDS. If you keep on top of your sediment and carbon filters, then the membrane will last longer. A membrane will also last longer when a water softener system is used before the system.
Also, to make your filters and membranes last longer, make more water at a time. For example, don't make a gallon at a time. Make 20 or 40 gallons.
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OP
OP
I'm making 30g's at a time, 2x a month. Tested this morning and TDS from tap is 150, bypassing DI is 9. Is this ok? Good bad?
If your tap water is 150, and the water coming out of the membrane (before the DI) is 9- that sounds like your system is working great!
Much higher than you should be seeing actually. At 96-98% rejection rate which is what you should expect the RO only TDS should only be between 3 and 6 at the most. A TDS of 9 means your membrane is only 94% rejection rate. For every 2% you bump that up you double your DI life so a more efficient membrane would pay for itself pretty quickly with a 4% improvement of more since your DI would last at least 4-5 times longer if not more.
As an example my tap TDS is around 560, I do use softened water and my RO only TDS is between 2 and 3. My DI lasts well over a year and I make water for both a 100G display w/30G sump and a 16G nano. If my RO membrane were only 94% versus the 99+% it is the RO only TDS would be like 36 or 37 and DI would last me less than a month. More efficient systems pay for themselves.
As an example my tap TDS is around 560, I do use softened water and my RO only TDS is between 2 and 3. My DI lasts well over a year and I make water for both a 100G display w/30G sump and a 16G nano. If my RO membrane were only 94% versus the 99+% it is the RO only TDS would be like 36 or 37 and DI would last me less than a month. More efficient systems pay for themselves.
Trex
Valuable Member
Depends on which RO membrane you are using. Need to know the rejection rate of your membrane. For me (( I have similar tap TDS )), that would be too high, and would change out my membrane --- I use the DOW FilmTec 75 membrane.
Randy Holmes-Farley
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I agree it depends. That's typical for me. Incoming ~100 ppm TDS, after RO, 9 ppm TDS. 
Randy Holmes-Farley
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I don't think that 2% = doubling is the best way to calculate the DI life. I expect you know this and are just oversimplifying for people, but it can lead to misunderstandings. Going from 94 to 98% rejection (the 4% example you give) is not 4-5x, but rather 3x.
In terms of the 2% increase, it matters entirely where you start. Going from 90% to 92% rejection is only a 25% increase in lifetime and going from 97 to 99% is a tripling in the DI life. 97.5 to 99.5 is a 5x increase.
OP
OP
My membrane comes from BRS, Dow Filmtec 75gpd. Never been flushed. Bought 2/17/14 It hooks up to my tap, where the water is turned up all the way. I do get some dripping from where the unit connects to the tap.
Really, it would be your call on the filters...
However, the sediment filter that we sell is a 1 micron sediment filter. It would pull out finer grains of sediment than a 5 micron which would mean less sediment clogging up your membrane... - AquaFX Sediment Filters
However, the sediment filter that we sell is a 1 micron sediment filter. It would pull out finer grains of sediment than a 5 micron which would mean less sediment clogging up your membrane... - AquaFX Sediment Filters
