RO/DI advice

[Mihai]

Hi,

I'm looking for an RO/DI unit and I'm a bit puzzled: at the online stores (see sponsors) such a unit is around $200, however on ebay they are all closer to $100 and under (see below). Is it anything wrong with those products?

Also, I heard the chloramine is really bad for the RO membrane. The carbon filters on the other hand remove chlorine, not chloramine right? Does this mean the the chloramine goes through and will damage my RO membrane?

Thanks for the help,
Mihai




$78
Model: RO6100DINT
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... gory=20756


$61
Aqua-Safe TM MODEL 2004C + 4DI filters
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 2381005664


$88
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 2380820332

 

[FranklinP]

I just bought the "reef master" unit from these folks. Seemed like the cheapest considering all the options it comes with. Guy was very helpful on the phone. Remeber this is a rO and DI unit. Has all the stuff to setup a storage container too. Also comes with back flushing capability included. This is not a drinking water setup like the ones on E-bay it is made for a reef system. Of course you can still drink it.

http://www.osmoticwaterfiltration.com/Products.htm

 

[Mihai]

What are you talking about? How can $195 be the cheapest?
All thee options I showed you are less than half the price of that!
You must be the owner of that joint...
M.

 

[psiico]

Wow, those are good prices. I don't know squat about RO but they look good to me. I don't have an RO yet, I'm just using a TWP sometimes and buying water sometimes. Is there a standard size cartridge and membrane? If so you can use one from another company if you're that worried about quality.

 

[FranklinP]

The system I bought comes with all the stuff to work with a reef system and has the DI option. No I dont own the place. You get what you pay for. Good luck.

 

[Mihai]

Man, that's why I'm asking: I'm trying to make sure that I don't screw up and buy something useless. To me they look good (they have all I need!), but I don't own a system and I don't know if something essential is missing. That's why I'm asking Franklin. What I'm looking for is advice whether that is good stuff or not, rather than pointers towards more expensive items (which again are all over sponsor's pages).

Regards,
Mihai

 

[kim]

There's nothing special about RO and/or DI units used for reefs. Nobody out there makes them especially for reefers, though some seem to sell them.

However, there are different quality membranes and different types of DI resin. These are almost all interchangeable....the canisters used have standard sizes.

If you have standard water, a standard RO/DI is probably fine, EBay is a good source. As a reefer, you will however be sensitive to stuff like silicates, which would not be of concern to many others. If your water has a lot, then a particular membrane, and a certain type of DI may be warranted.

It may be worth buying from an established company initially, then sourcing spares elsewhere. Depends....it's an important issue, you want to get it right, how much background reading do you want to do, how much can you take in ? You can save US$ 100 easily, but if it takes you four weeks to work out what you need and then find the serial numbers of the components you want, that may be a bad deal too.

And before buying anything, know your water quality.

kim

 

[vair]

Those prices seem cheap and they do look good. I'll I can say is I would error on the side of caution. (is that how that saying goes?)
I purchased mine at http://www.airwaterice.com/ and have been happy with the unit, great service.... and no Mihai I do not work for them or anything.

Dave

 

[Mihai]

Thanks for the advice. Sorry for the working for them stuff... I wasn't thinking clearly (or clearly not thinking).

Mihai

 

[sambo1]

I bought a Typhon from airwaterice.com. Little more $'s, but have never heard anything bad about their RO/DI's or their customer service. My first impressions of them are top notch.

 

[Exburb]

And before buying anything, know your water quality.

I have well water. What kind of test readings would I be looking for to justify a RO/DI purchase?

 

[kim]

That's a toughie.....I just had my utility send me their standard "quality" report, which covers pretty much everything - metals, salts, organics - and was not something I could hope to reproduce myself. It was then simple to go down the list.

Do laboratories provide an equivalent service for well users (not many of them in the UK, so I just do not know how you go about things) ?

At a basic level, you could yourself test for conductivity (an indication of the total dissolved solids "TDS" in the water), phosphates, silicates and nitrates. But note that if you live in an agricultural area, use of fertilisers can make these quantities seasonal so you might miss them. I would also be tempted to test copper, not sure how accurate the kits are.

Anyway, for starters you need zero phosphates and copper, maybe less than 1 ppm silicates and less than 10 ppm nitrates. Anything worse, and you probably should use RO and/or DI.

If you have low TDS (eg less than 50 ppm) you could use DI to purify the water, but if TDS are higher, RO might be better since DI will quickly be saturated.

If you have high silicates (eg 30 ppm or above) then I would suggest considering an RO membrane with a high silicate rejection rate, and/or a specialist DI resin, but I am not an expert.

And if in doubt, I would recommend RO/DI and use the above tests as a guide to purchasing the correct unit. Whenever a reef tank has any kind of problem finding the source is difficult - at least using a known quality of water eliminates one area of doubt.

Testing for the items above is a good start, I am just not sure that it is exhaustive enough to allow total confidence. You should definitely get some additional views on this and not rely solely upon this one. Spectrapure is a manufacturer of RO/DI kit that has a "sponsors" forum on Reef Central. It might be worth asking them what parameters they would want to see. I am not connected with the company, but they do have a good reputation for advice.

Hth,

kim