ro/di units

tellycoleman · 05-29-2007, 11:47 PM

has anyone had any success using ro/di units shown on ebay?
they are priced cheap and i was wondering if the do the job.
example http://cgi.ebay.com/AQUARIUM-2-110GP...QQcmdZViewItem

also has anyone had success using a ro/di storage tank in combination with a sump auto top off system?

Hop · 05-30-2007, 12:06 AM

This is likely as big of a debate as skimmers, but I'll try to throw my .02 in without starting a free for all.

These cheep, import units on e-bay look appealing, but in the long run are not worth the expense. They use cheap filters that don't last and some, but not all have irregular sized canisters that won't accept common quality filters. You can buy a quality no frills RO/DI for around $150, with quality and properly sized filters and quality membrane with a full sized DI unit. To buy a cheap unit like the one pictured, and then replace the filters, you’re looking at exceeding the cost of buying a quality unit the first time.

It's pretty bad when you speak to some of these dealers online and they cannot even tell you the micron size of the cartridges or the manufacturer of the membrane.

And yes, I have a RO storage tank which supplies my sump. I do not recommend plumbing a RO unit right to the top off.

Fly Guy · 05-30-2007, 12:12 AM

Quote:

Originally Posted by Hop

This is likely as big of a debate as skimmers, but I'll try to throw my .02 in without starting a free for all.

These cheep, import units on e-bay look appealing, but in the long run are not worth the expense. They use cheap filters that don't last and some, but not all have irregular sized canisters that won't accept common quality filters. You can buy a quality no frills RO/DI for around $150, with quality and properly sized filters and quality membrane with a full sized DI unit. To buy a cheap unit like the one pictured, and then replace the filters, you’re looking at exceeding the cost of buying a quality unit the first time.

.

The Filter guys, AirwaterIce, and Spectrapure. Cant go wrong with any of them. All quality and all stand behind their products with excellent customer service.

Hop · 05-30-2007, 12:17 AM

LOL. Still being new here I didn't know what links I can post or not yet

But yes those are great!

frankandmaura · 05-30-2007, 07:30 AM

I have one from Aqua-Safe:

http://stores.ebay.com/The-Aqua-Safe...eNameZl4QQtZkm

That is the company website...I got the this unit...This is a very good unit...and I am very happy with it. Comes with everything you need.

http://cgi.ebay.com/AQUA-SAFE-MAXIMU...QQcmdZViewItem

I do not believe this is a cheap, crappy unit...from what I understand this is the unit (or some variation of) Coca-Cola uses for Dasani water.

Just my $.02

Hop · 05-30-2007, 09:30 AM

I think your OK with that one. I was directing my concerns over the units running under $100... I'm not an expert, but I know one who plays something on tv

ckusnierek · 05-30-2007, 09:41 AM

I have one of those water generals and love it. It does take standars size filters. Been using it for about 3 months and no problems. I wish it has clear canister so you could see the filter conditions. It does have a clear DI chamber with color changing media. I suspose you could buy clear canisters is you wanted to.

I got the seller to throw in a 5g pressure tank which makes my 5g WC a peice of cake!!!

Hop · 05-30-2007, 09:49 AM

The PVC housings are nice as they are a little more resiliant against drops and mishaps. I have been running a no frills melev's reef RO/DI for about 5 years. I'm on my second membrane and have made somewhere near 10,000 gallons with it. My TDS going in is near 450 and 2 after the membrane with 0 after TDS, so I can't complain. I am looking at upgrading to a filterguys unit with some bells and whistles and the second piggybacked membrane soon though. When making 2-300 gallons a week, I don't like putting out quite so much waste.

VWD · 05-30-2007, 10:06 AM

I myself Like spectrapure, You pay more but they are very good, I have seen alot of people buy from e bay and are happy with them,

HowardX · 05-30-2007, 10:32 AM

The problem with some of the cheapo imported units on Ebay is they come with low quality off brand pre filters and membranes which have poor rejection rates and thus expends the DI resin very quickly. I would always get a top quality unit like the brands mentioned above with a Dow Filmtec 50 or 75 gpd membrane.

talon4x4 · 05-30-2007, 11:08 AM

I've been using an eBay unit for a couple months now with no problems, this one to be exact (I did add a post carbon filter which isn't on the auction below), http://cgi.ebay.com/ws/eBayISAPI.dll..._promot_widget

I also purchased a TDS meter which shows everything is working as it should. TDS IN = 135, TDS OUT = 0. The fish seem to like it just fine as well.

pipermacwills · 05-30-2007, 01:38 PM

I think all of the suggestions are good. I strongly concur with using the DOW membranes. I have used several different manufacters but this brand is the most durable. The 2 most significant aspects of membrane life are pretreatment and incoming tds. All I'll say is carbon, carbon, carbon. Just my 1.5 cents.

Laggs2003 · 05-30-2007, 05:50 PM

talon thats the same one I have and its been working good for the past couple months ive had it

Hop · 05-30-2007, 07:19 PM

Quote:

Originally Posted by talon4x4

I've been using an eBay unit for a couple months now with no problems, this one to be exact (I did add a post carbon filter which isn't on the auction below),

Why? Adding carbon after the fact will actually add TDS and phosphates... It's great if you are drinking it, it helps with the taste, but not your tank