Buying RO/DI unit question!

V

Vindicator

Member
Hey guys, Iv been looking at RO/DI filters the past few days, and I am having trouble deciding the best buy. First of all I am alittle confused. It seems like every aquarium dealer I have checked at sells the units for 200+ dollars. Nothing really cheaper than that. BUT I see them on ebay for around 135 bucks! And they are rated around 100gph. Why the price differance? What is going on? If anyone has bought one off of ebay without problems, do you have a good site? or can point me in the direction of a good ebay unit?

I am just really confused about the price difference.
 
Varga

Varga

Well-Known Member
I bought from filter direct on Ebay $125

my LFS sells the exact same unit for $250.
 
corrado007

corrado007

Active Member
It would be worth your time to check out these guys
RO/DI Systems
Just give them a call, they're very friendly and informative and won't try to sell you anything you don't need. A number of people here on RS have these systems and are quite happy with them.
 
cioutlaw

cioutlaw

Well-Known Member
Not all RO/DI systems are the same. I wouldnt buy one without a DOW filmtec membrane for starters. presure guage before the membrane & inline TDS meters are a must in my opinion. Do a lot of homework. Aqua FX is a RS sponsor & I am very happy with the unit & service I recieved from them. Im sure there other great companies too, Do your homework & ask lots of questions before you buy.
 
B

BobBursek

Active Member
DONOT buy one on FleeBay!!!!
thefilterguys.biz
buckeyefieldsupply.com
Check out these guys, call them and discusss your needs with them, they are great source if knowledge for the person who is not informed on RODI units.
 
BuckeyeFSupply

BuckeyeFSupply

Member
Some things you'll want to look for in an RODI system configured for reefing use:

Standard-sized prefilters, membrane, and DI cartridge
Brand name, high-rejection membrane
Specifications provided for each stage
Pressure gauge after the prefilters and before the membrane
Thermometer
DI bypass
Vertical DI stage
Refillable DI cartridge
Aluminum bracket
Quick connect fittings
Flush valve
Clear housings
High-quality instructions
Customer support after your purchase

Also, and you think this might go without saying, but seeing what is for sale on the auction webiste I guess it needs to be said: A system should have filters that are in the correct order.

Russ @ BFS
 
saltysupply

saltysupply

RS Sponsor
I always recommend aquafx, they are great people and right down the road from me:) The units are awsome as well and made with the best of the best parts available...they are also one of the few to offer chloramine blasters.
 
B

BobBursek

Active Member
Sorry to burst your baloon, JUNK!!!!!!!!! Sent it back or cancell the order!!!!!!!! First a all 100gpd have a lower pure water rate out of the RO then lowergpd units so you will go thru more DI to get 0 TDS, 2nd a good ro membrane can last for years and DOES NOT have to be changed every 6-12 months as they state, 3rd because DI canisters are not fully preasurized, you donot want horizontal ones, you want them to be vertical, the water going thru the resin will only contact the lower 3rd of the resin on that one and not utilixe all of the resin. You did NOT listen to me and do your home work and call Buckeye or Jim at Thefilterguys,and talk to them, your getting ript off, what you save now you will pay more. Then you will be back here trying to get info on all your problems with your RODI system as to why your TDS's are high after a couple hundred gallons!!!!!!!!!!!!!!!!!!!!!!!!!!! Sorry but facts are facts!!!!!!!!!!!!!
 
B

BobBursek

Active Member
Sorry Vindicator, I directed that post to you. It should have been to RCPilot. If you look at the unit he bought you will see what I am talking about! The DI are not standard size either!!
 
Origami2547

Origami2547

Member
I bought my RO/DI setup (a Typhoon III) at airwaterice.com (AWI) and have been happy with it.

Bob has a point, a lot of 100 gpd membranes ahve a stabilized rejection ratio that is less than many of the 75 and 50 gpd membranes (90% vs 98%). That means that less is removed by the membrane and is left to the DI resin to remove. That, in turn, means the DI resin will not last as long before needing to be replaced or recharged.

However, there is a 150 gpd membrane available with as good a rejection ratio as the smaller membranes (98% efficiency), so the argument is not without exceptions. (See here: the complete FilmTec line of nano and reverse osmosis membranes

Check out the FAQ at AWI if you want to learn more about RO/DI systems in general.

BTW, I've also heard good things about The Filter Guys....
 
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