RO/DI issue

scuttlebut

New member
I'm ready to purchase my RO/Di unit. Is there an advantage to a 6 vs. 5 stage unit? From what I understand the 6th stage is mainly for use with a RO faucet and storage tank. Am I wasting money by purchasing a 6 stage unit?
 
Money is not the issue....do I purchase a 4, 5 or 6 stage system. The water entering my home is quite cold high 50's low 60's @ 75 psi. So whatever I get will make RO water slowly. What is the advantage of one type/brand over another?
 
the diff. are 75 gpd membrane over the 100 gpd membrane that that one has. the 75gpd is 98% rejection rate where the 100gpd is only around 90%

the DI (get the horazontal vertical mixed up) but you want the one that is up down not side to side it will work much better.

I actually own a filter like the one your looking at and all i use it for is drinking water but also own a purelyh2o optima pro unit that i use just for my reefs.
 
The number of stages doesn't mean a hill of beans! E-bay vendors try to impress people with worthless garbage like that.
Its what the stages contain thats important period.
You only need 4 stages and thats it.
1. High quality prefilter, the lower the micron range the better. I use a 0.2 micron absolute rated prefilter
2. High quality carbon block. You only need one as long as it is a quality carbon like a Matrix Chlorine Guzzler in the sub 1 micron range. I prefer the 0.5 micron variety good for 20,000 gallons of normally chlorinated water.
3. A high quality RO membrane. The 75 GPD Dow Filmtec is the industry standard for a reason, it is 96-98% efficient and produces 75 GPD at 50 psi water pressure and 77 degrees F water temperature. Others may take up to 65 psi to produce the same amount of water. Do not get a Dow Filmtec 100 GPD membrane or one of its falsely advertised variants as it is not even a RO membrane at all but is a 90% efficient nanofilter not approved for drinking water in the USA by ANSI/NSF the organization that tests all things that come into contact with drinking water. Don't fall for the 110 GPD or 125 GPD stuff as no American manufacturer makes a RO membrane in those sizes. Some vendors even use Chinese or Taiwanese clones that are not certified for sale in the US and try to pass them off as American made, don't believe it!
4. A standard sized 10" vertical 20 oz DI canister and refillable cartridge. Often e-bay vendors use little tiny horizontal hollow tubes and try to pass them off as DI filters. Some only hold 6 oz of resin and even then water can and does bypass the resin for really poor treatment.

Read through some of the e-bay ads and look for red flags like the lack of brand names on filters and membranes, the lack of micron ratings on filters, really bad math like claims to be 99% efficient but when they show readings its something like 300 TDS tap water and 30+ finished water! Thats not 99% efficient in my book? If they don't tell you the membrane is made by Dow Filmtec, Applied Membranes or GE Water you can bet its imported junk every time. Good vendors are proud of their units and will tell you up front what goes into it, no secrets no surprises!
 
Well AZ that really sums up what I needed to know. With a good quality unit like the one you describe how will the extreme cold water affect the output volume of the unit. Will increasing pressure in my line compensate for the cold water?
 
<a href=showthread.php?s=&postid=11647430#post11647430 target=_blank>Originally posted</a> by scuttlebut
Well AZ that really sums up what I needed to know. With a good quality unit like the one you describe how will the extreme cold water affect the output volume of the unit. Will increasing pressure in my line compensate for the cold water?

IMO, with water as WARM as 50's and 60's should make water fine at a good rate. :D I could only wish for water that warm, during this part of the year our cold water sits at just a few degrees above freezing (sometimes as low as 34 degrees) and I still make water at an acceptable rate. Certainly not as fast as in the summer (where our water is still colder than 60's) but still plenty fast using a 75gpd membrane.
 
Yes, increased pressure can help with cold water. Take a look at the Calculator on the top of the page here:
www.buckeyefieldsupply.com for good accurate estimates of anticipated flows at different temperatures and pressures.

A 75 GPD Dow Filmtec membrane gives you 75 GPD at 50 psi and 77 degrees. Others like GE Water and Applied Membranes require 65 psi to produce the same 75 GPD out of their 75 GPD membranes. Their 100 GPD membranes are comparable to the Dow 75 GPD but do not get a Dow 100 whatever you get since its only 90% efficient and wil eat DI resin for lunch. For every 2% you increase the RO membrane efficiency you double the life of DI resin so the difference between 98% and 90% efficient is huge.

Booster pumps can be used to increase pressure but Dow also offers a 150 GPD membrane that should be 96% efficient anyway. I think Buckeye carries those too.
 
AZ if you were to purchase a new unit what would you get? I'm new to this stuff again after many years away and it's like learning to ride a bicycle all over again.
 
I wanted the very best so I bought the Spectrapure MaxCap. If your tap water is very bad at all its definitely worth the money. If you have what I would consider average or better tap water there are several units that fit the bill in the $150-$230 price range for everything. Buckeyes 75 GPD Premium systems is hard to beat at $161. Other units that are very similar in both price and quality are the Ocean Reef+1 from www.thefilterguys.biz , the Optima series from www.purelyh2o.com , Reefkeeper from www.melevsreef.com and the Typhoon III from www.airwaterice.com . All are very good units. I suggest calling or e-mailing all of them with your needs and see what they say.
 
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