RO/DI question

Hi there,

Another one of my foolish questions incoming .

As some of you know im starting to set up my system now, so far i have an aquarium ive just finnsihed building my stand for it, got drillpieces on the way to drill a hole for the sump im picking up tomorrow.

Now im getting ready to fill the baby up with water! And i got a but puzzled...

Over here in sweden i can only find water filters that look like this...

Köp & Sälj på Saltvattensguiden.se - Aquatic Nature Osmos - Powered by PhotoPost Classifieds

And they only seem to call them Osmosis filters... My questions is... How vital is the DI in RO/DI?
Over here the water is very clean (where i live has among the cleanest tapwater you can get)... Could it be that it just isnt needed, or are the swedish shops once again hmm... how to say it... crap

My tank is about 100G with the sump. Could anyone recomend me a decent RO/DI unit? or would one of these overpriced swedish ones do? Also is there a real quality difference between the cheap / expensive ones, Or can you get by pretty well on a cheap one from HK?

Thanks in advance

 

The DI (de-ionization) removes the last impurities that the RO (reverse osmosis) membrane can not. It is quite important for removal of heavy metals, nitrate and phosphate.

 

Welcome to 3Reef!!!

One very know unit in the business is Spectrapure.

SpectraPure Water Purification Products

It is important to get a true RO/DI unit and not just an osmosis unit. You do not need to break the bank on this, but make sure you are getting a good unit with quality components that can be replaced easily when they are due to be replaced.

Good Luck!!!

 

Thanks for the help you two, amazingly fast and informative posts

RO/DI it is then Now i just need to find somewhere in this country that actualy sells a unit (for under 300% of the us price >_>)

 

Best of luck

 

Hi,

Anyone have any experiances with this unit? Phoned a few shops close by and a 2 stage one costs over $150 here so i think ebay is the way to go

6stage 100GPD

REEF & HOME DRINKING RO DI REVERSE OSMOSIS WATER FILTER on eBay (end time 18-Aug-10 04:01:01 BST)

 

you are doing exactly what the Ebay vendors are hoping for and it is the worst possible thing to do.

Ignore the word "Stages" completely. This is how they hook you and reel you in. The word stages doesn't mean a hill of beans and more stages is not better, in fact for a very high end RO system you want 3 stages and for RO/DI 4 stages, thats it, no more.

First off the ebay systems are very low end drinking water systems and not the same as a reef quality system. Since they are such poor performers they have to add a gimmick or way to entice you to buy their imported Chinese clone systems so they tack on more useless 'stages" to make it sound like the best thing since sliced bread. More is not better.

Take a look at those "stages". First they use a 5 micron nominal rated prefilter which is pretty coarse and allows particulates and colloidal materials to get to the carbob block and fould its pores rendering it useless for chlroine removal. next they use two carbon blocks of an unknown brand and micron size or chlorine adsorption capacity.
Then they go to the membrane or fourth stage which is more than likely a GE Osmonics or Desal membrane comparable to the Dow Filmtec 75 GPD.
Next they go to a little dinky 6 oz hollow tube they call a DI filter then finally through an inline carbon taste and odor filter which actually adds TDS back into the treated water.

Now lets look at a popular 90 GPD reef quality RO/DI system that sells for $145 complete.
It starts with a 0.5, thats 0.5 not 5.0 micron absolute rated prefilter so is extremely effective at removing up to 99% of all sediments. particulates and colloidal materials down to and including 0.5 microns unlike the 5.0 nominal that only has to remove about 85% of things at 5 microns and is by definition able to pass 15% of things larger than 5 microns on to the carbon block.
Next it uses a single 0.5 micron near absolute rated carbon block good for 20,000 gallons of normally chlorinated water where the unnamed ones may do a maximum of 1500 gallons total. Remember all water passes through the prefilter and carbon block so 1500 gallons is only 300 gallons of treated water and 1200 gallons of waste at the industry standard 4:1 waste ratio.
Next it passes through a batch tested 90 GPD RO membrane that averages better than 98% rejection or removal efficiency.
Finally it uses a full size industry standard 10" canister and refillable cartridge type DI filter that holds a full 20 oz of DI resin compared to the other one at only 6 oz and horizontal too so it short circuits or channels and is very inefficient.

The good one also comes with a dual inline TDS meter, an inline pressure gauge, a capillary tube type flow restrictor and a written warranty backed by a company doing water treatment in a brick and mortar building in the same city in the US for over 25 years, no Chinese or Taiwanese imports.

For the $145 my money is on the second one. There are other comparable units too from other long time US vendors for less than $200 all over the reef forums and you can probably get them in Europe too.

The thing I am trying to convey is stay away from ebay when it comes to RO/DI, you really do get what you pay for and the difference is night and day.

 

Does anyone know a place that sends good stuff abroad? sadly prices on these seem to be completly insane n europe and i dont really know what makes to go for since they sell different makes over there ...

Also checked some swedish forums but it seems people are just trying to get away as cheap as possible with all there things on there. Most of the links are ordering stuff from china and that gives me bad vibes

Is there any chance someone could help me find one for ~the $150 mark either on ebay or some site that ships abroad since im honestly clueless when it comes to this

 

Anyone who can write a short lists of good trustworthy brands instead, maybe if i crosscheck with the german stores i can find one :/

//Person in need of help

 

If you have that unit in your first post and you said you have good water over there in Sweden, I would check the TDS of the water coming out that unit, to see what it reads. Then, you might be able to just hook up the DI canister to that one to bring the TDS down even more. Just my 2 cents!