R all RO/DI's created equal? This one worth buying?

Neighbor and I are going to go halves on an RO/DI filter. Just wanted to know if all 4 stage or 5 stage or anything else are all created equal?

What sets different brands apart?
Basically what should I look for when purchasing?

Is there a big difference between brand name and some off brand ebay stuff?

 

There are, like anything, good ones and bad ones. I've had success with the Typhoon III from Air Water Ice. Lately I've been hearing great reviews about SpectraPure. To some extent it's a preference thing.

 

For example, when I compare the description of SpectraPure with that of an off brand ebay item they both read the same. So to me it seems im just paying for the name.

 

I've never used SpectraPure, so I can't speak for its effectiveness. IMO, there is usually a reason why one is a brand name and one is an off brand. Usually the brand name has to earn it somehow, often with a good product.

 

A 2 micron filter is a two micron filter. A carbon block is a carbon block. Resin beads are resin beads. RO membranes can differ, but if you look at comparable brands, and compare apples to apples, you will find most use the same filter. After that it is down to dollars and features. As with anything going cheap is usually the more exspensive way to go. Stick with a quality brand. Bulk Reef Supply, Spectra pure, Filter guys.... ect.

 

The big difference if filtration. The housing is basically the same. You could buy the most expensive model out there and it work great then when you change the filters on it go cheap and it not work worth crap after. The better "or brand names" have better filters from the start. So if you go cheap on the RODI then you will get cheap filters. This is where they save and can offer a cheaper unit.

 

spectrapure is probably the best IMO

 

No, there are huge differences, even though they may appear the same visibly its what is under the hood, or inside that counts.

You will not find one on ebay that compares to the Spectrapure guaranteed.

Look for a name brand RO membrane, Dow Filmtec, GE Water and Applied Membranes are the big three. If its a Dow Filmtec you want the 75 GPD, not the 100 GPD at all costs, it is the absolute worst choice on the market as it is designed for Pool and Spa Use and not drinking water. (Spectrapure starts with the Dow 75 then treats it with a special proprietary process then eithe batch or hand tests it for quality control and performance, they are the only vendor to offer this service and guarantee).

If it is a GE or Applied you want the 100 GPD as it is really identical to the Dow 75 in truth. They all do 75 GPD at 50 psi, 90 GPD at 60 psi and 100 GPD at 65 psi, its just the way they advertise them.

Look for a full size 10" vertical prefilter is a 1 micron or less size, small er is better and absolute rated is better than nominal rated, Spectrapure uses 0.5 micron absolute in their reef quality systems.

Look for a single 1 micron or less carbon block, you do not need two and high micron blocks area waste of money. Consider one 0.5 micron carbon block will treat 20,000 gallons of normally chlorinated water. A 1 micron will do about 9,000 gallons, a 5 micron about 6,000 and a 10 micron as little as 1,500 gallons.

What that means is at the normal 4:1 waste ratio all membrane manufacturers recommend you get 4,000 good and 16,000 waste out of the 0.5, 1,500/7,500 out of the 1 micron, 1,200/4,800 with the 5 micron and only 300 treated gallons and 1,200 waste gallons out of the 10 micron. The lower the micron rating the longer they last and better they work. One good 0.5 micron will outperform 2.5 or more of the others.

Look for a full size 20 oz. vertical refillable DI canister and cartridge. Small horizontals are very inefficient and usually hold much less resin which tends to channel or short circuit for bad treatment.

Look for a capillary tube flow restrictor you personally trim for the optimum waste ratio. Most units on the market come with non adjustable one size fits all restrictors and you know nothing is ever one size fits all, all our conditions are different around the country.

Look for a TDS meter, either dual inline or handheld, I actually have both and use the inline as a rough guide and the handheld for accuracy on the RO and DI ends.

Look for a inline pressure gauge as pressure is an important piece of the puzzle. You need an absolute minimum of 40 psi and more is better up to say 90 psi.

Look for John Guest style push in or speed fittings. Many ebay quality systems still use the old style compression fittings and they can be a pain. Look for quality housings, brackets and hardware. Again they all look similar so you must trust your vendor. Someone on ebay with a warehouse or shipping container of Chinese clones is not going to be using name brand parts at a $59 price tag. Someone like Spectrapure or AWI who have been around for 25 years or more will.

DO NOT get hung up on the word "STAGES". More is not better, what is inside is what matters and a 4 stage can and often will outperform a 5, 6 or 7 "stage" system. Its all about the filters and look at it as a system from start to finish, you could have the best membrane in the world but of the prefilter is junk it will not perform as well or last as long, driving the cost of ownership up.

Its kind of like a fine toll, pay more upfront for quality and it will reward you in the end.

Ones I recommend are the CSP-DI or MaxCap found on sale here:
SpectraPure Customer Appreciation SALE! 20% - 50% off

The 75 GPD premium found here:
http://www.buckeyefieldsupply.com/showproducts.asp?Category=168&Sub=166

The Optima Professional found here:
Aquarium RO DI Systems

And I even buy some of my stuff here:
Replacement Water Filters | Reverse Osmosis | Big Blue Water Filters |

There are many other good ones out there but either they still use the old school dual carbons, use a poor filter combination or their prices are not competitive.

 

AZDesert, perfect. That was exactly the post I was looking for.
K+

 

To add to that.
A few things you might find useful are a DI bypass valve which allows you to use RO only water before DI for such things as drinking and cooking. Its a simple tee and ball valve, sometimes with a check valve too that fits in the line between the membrane and the DI filter. $10-$15

Another is an autoshutoff valve (ASOV). This allows you to fill a trashcan or ATO reservoir, or a pressure tank in the case of a drinking water or dual home/reef type system. When the ASOV senses backpressure from a close float valve or float switches and solenoid it shuts the RO and waste flows off automatically so you can make water unattended. $12-$15

Things that have no proven value are "flush valves" or flush kits. They sound like a good idea but they really do nothing other than give you a warm fuzzy feeling. As long as you keep your waste ratio at close to 4:1 you are providing the best you can for the membrane. If you want to flush something use the DI bypass valve I suggested above and manually flush the first few ounces or high TDS creep water out before it gets to your DI resin, this provides some value but requires you be there when you make water so automation is a little tougher. I still like a DI bypass though as it gives me a point to draw RO only water for testing with my handheld TDS meter.

Other ebay sales gimmicks are multiple horizontal DI filters making you believe if it has to travel through two or three little dinky horizontall filters its perfect. Thats not really the case as they all channel and short circuit and you still get lousy treatment. Or large micron prefilters which allow particulates and colloidal materials to pass through and foul the carbon block, always go with a prefilter the same size as or smaller than your carbon block so the carbon can do its job and the billions of tiny pores do not get plugged or fouled. Let carbon act as carbon not a prefilter.

One added bonus with companies like Spectrapure is they build their units one at a time to order so you get the freshest DI resins and it has not been sitting on a shelf somewhere. They will also install any options you order such as the ASOV or DI bypass for you since it is being built the day it ships out. I believe a few others offer this too but you would have to check.