RO/DI Filter questions

There are a lot of good RO/DIs out there Spectrapure, BRS, Air, water and Ice and the filter guys. I currently have a 300gpd from Air, water and Ice and buy filters from BRS or the Filter Guys. I've owned a slower Spectra pure for many years. We are currently looking at a 125gpd from Spectrapure that makes 2 gallons of RO/DI with 1 gallon waste.

 

I have owned the MaxCap UHE ultra low waste system for about two years now, its awesome. It replaced a dual membrane MaxCap which replaced a 90 GPD MaxCap which replaced a Typhoon III which replaced a Watts Premier etc. Constantly looking for the better mousetrap and I have found it so far.

Make usre the replacement filters are of the same or better quality. I am not aware of anyone who sells a 0.2 micron or 0.5 micron absolute rated prefilter like Spectrapure. There are no other vendors that custom mix all their DI resins based on bench and beta testing results and no one else tests their RO membranes and treats them with a special proprietary process to further improve their efficiency. Make sure it is apples and apples and not apples and oranges, there really is a difference.

 

So, Should I get the MaxCap, or CSPDI. Whats advantages does the MaxCap have over the CSPDI. If I'm not worried about stages, then the CSPDI seems more appealing for the 150 price tag

 

But if I get what they "promise" and do so consistently, I wouldn't actually worry about all their "special" tests. What really matters is how the unit performs, what their customer support is like and overall general consumer satisfaction.

 

The Spectrapure MaxCap has the only 100% indiviually hand tested RO membrane in the industry. They treat the membranes with a special wet process then test them one at a time. The membranes are guaranteed in writing to be better than 98% rejection rate, the average off the shelf dry Dow Filmtec (which is what the SpectraSelects start out as by the way) are around 97% based on thousands of membrane bench tests. My personal system has averaged 99.35% over the last 23 months since new. My MaxCap before tha taveraged 99.23% until the day I sold it. That extra 2% rejection doubles the life of your DI resin no matter whose resin you use.

No other vendor guarantees their membranes beyond what the manufacturer offers, and thats 96% stabilized rejection with 98% maximum rejection.

The MaxCap offers the individually hand tested and guaranteed RO membrane, the CSP-DI has a treated but only batch tested membrane, probably close to the same performance but not guaranteed in writing. The MaxCap includes the MaxCap DI cartridge along with the SilicaBuster which extends the life of your DI at least 3.5x over any other. The MaxCap also includes a second dual inline TDS meter for 4 TDS measurements.

If your tap water TDS is anywhere near the national average of about 250 then I would opt for the MaxCap. mine averages between 650 and 850 and my MaxCap TDS averages between 4 and 5. If your TDS is say in the 100-200 range or if you are on a budget the CSP is an excellent choice.

It all comes down to long term cost of ownership, the less often you replace the membrane and DI the cheaper it costs over its useful lifespan. I figure my first MaxCap was paid for in less than one year and I now make water for less than a nickel a gallon including the water andsewer rates, taxes and tariffs and replacement filters and resin, thats pretty cheap.

But what do they "promise"? That you will be satisfied, and of course if you have never owned another RO/DI or upgraded froman ebay system you would be satisfied. If you have owned a better system or have something to compare to the satisfaction is not there. Having owned a Typhoon III which I fet was the best at the time, I can say theer really is a big difference and major difference in the long term cost of ownership and treated water quality.

 

I'm not saying go "off brand". Those are definately questionable. I'm talking about the major ones I listed. They are all well constructed and supported with great consumer satisfaction. I would look through those and see which has the features you want..... you can't go wrong there, IMO.

 

You are missing the point, they are not the same. Look for a hand tested and guaranteed better than 98% rejection rate RO membrane somewhere else. You will not find one. Look for custom blended DI resin based on real world testing, you won't find any. Look for a capillary tube flow restrictor, you will only find it at Spectrapure and Buckeye Field Supply. Look for a written performance guarantee, you won't find it. Look for a pleated absolute rated prefilter, you will not find it except at Spectrapure and Buckeye. There is a difference.

Sit down and calculate the cost of DI and membrane replacements over a 3 year period then reduce that number of replacements to less than 1/3, there is you savings. Talk to Randy Holmes Farley and ask him how long his last Spectrapure membrane lasted due to using high quality replacements, 10 years. You will not find that with other systems as they use nominal rated and usually higher micron rated filters.

Like I said before, if you have not tried one or know someone who has a MaxCap, you really cannot grasp the difference. Consumer satisfaction can be deceiving if you have not experienced anything else. I was happy with the 150 gallons of RO/DI I got per refill with my Typhoon III until I got 830 galons with my very first MaxCap cartridge! Thats more than the 3.5x extra life they advertise and its been over 1000 gallons the last several MaxCap DI cartridges and I have never replaced a Spectrapure membrane ever. Figure the cost savings bewteen 150 gallons per DFI and 1000 gallons per DI, it really that good.

The vendors you listed offer nothing unique, everything is prepackaged off the shelf for RO/DI. Look for innovators, someone who does research and testing and comes up with something better, not just an off the shelf system. I do buy things from Bulk Reef but not RO/DI supplies, I like my tank too much to step backwards. I used to buy from AWI but would never buy from Filter Guys, they are bad news and did me dirty in public, I won't forget it.

 

I've owned RO/DIs from 3 of those places and have bought filters from all 4

I guess what I'm looking for enroute to my final destination of good clean RO/DI is a unit with a great track record sustained for several years, a nice easy to maintain unit, good customer service if something goes wrong or I have a question, filters that last a long time for the output (I change my filters once it hits 1 and my tapwater TDS is frequently over 500)... that kindda stuff. I was not more impressed, but just as impressed with my Spectapure as I have with the other 3. If someone is looking more than those things I listed above, the above would be as good to them as they were to me.

 

TDS has nothing to do with when to replace prefilters and carbons, thats the job of the RO membrane and DI resin. Prefilters and carbons get changed at 6 month intervals and protect the RO membrane from TSS or suspended solids, things in the 1 to 10 micron range and larger. TDS or suspended solids are in the 0.0001 size range so the prefilter and carbon have very little to absolutely no effect on TDS or dissolved solids.

You replace the DI resin when you start to see anything other than 0 TDS and monitor the membrane performance too. My Typhoon III delivered a RO only TDS of 13-15 down from a tap water TDS of 830, the MaxCap is between 4 and 5 on average and sometimes lower, huge difference. I even removed the 75 GPD Dow Filmtec membrane from the Typhoon and had the engineer at Watts Premier bench test it for me and it was as good as it could do. There is a difference. Guess which membrane makes DI resin last the longest thus has a lower long term cost of ownership? Its an easy choice and I have log books of data to back it up.

 

Are you even referring to me?

To the OP.... The criteria I use when looking at new units are

• Proven track record with mainly good reviews (there will always will be those with bad).
• Reasonably priced filters that last a long time with average use and TDS (I'm use more water than average and have a higher TDS than average).
• Good customer support.
• Sturdy/high quality construction (and easy to maintain)

I have gotten these things from Spectrapure, BRS, The Filter Guys and Air, Water and Ice. I am your average aquarists with normal requirements and these have served me well.