Need info on RO and RO/DI units

[INXS]

Well I am concidering taking a plunge and getting an RO unit for some species that I am having a hard time with and also to try using purer water to induce breeding.

Since I know nuthin' , I figured I would ask the braintrust here - someone always seems to have experience with what ever it is.

I am looking at getting somewhere from 20-35 GPD and have looked at several models . From Bare Bones 20gpd for just over $100 to RO/DI Maxxima for $250

Questions:
What percentage purified water do you get from Bare bones vs RO/DI out of incoming water?
Does one waste more then the other?
How pure do you really need it to be - concidering you should mix it before adding to the tank?
What is the general cost for parts (filters , membranes, resin) on an annual basis using around 20 gal/per day (PH 7.8 GH10 incoming water) ?
How long is the life of the filters, membranes and resin?

Are there any brands to reccommend and to stay away from?
Thanks

[Barbie]

I've been currently shopping around for a replacement for my RO unit. The membrane is old I can't see spending close to what a new one costs to replace it. In my searches, I found These. The people that had ordered them at the aquarium advice forum had nothing but good things to say about them, and Stepchild recently purchased one also. They have a very high feedback rating, and the price for a 110gpd RO/DI is comparable to the price you had for a bare bones RO that only does 1/3 of the water. They also sell TDS meters for 25 dollars.

RO units do best if kept plumbed so the membrane never gets dry, according to the reading I've been doing on them. I intend to get some form of rheostat and plumb mine in so that it shuts the water supply off to it, without manually having to keep a watch on it. You can't use a standard float valve at your holding tank, as that causes back pressure on the membrane, so the flow needs to be shut off before the RO unit, by the float or whatever gadget you use.

On average, you'll waste 4 times the water you create, but that's a pretty broad average. If your water is already relatively soft it drops drastically, and in the hard water in KC (kh 17 and gH 25+, I got tired of adding drops) the output was literally running a hard steady stream, while the RO water line was barely dripping. It was sad. The DI portion of the unit just really depends on how much you use it, and what levels of phosphates and other wastes there are in your tap water for it to remove. I don't intend to use the DI portion of the RO unless I set another reef tank up, but I like knowing its there, if I do.

Bare bones and RO/DI will waste exactly the same amount of water, as they're both RO units. The DI process doesn't waste any. I would assume with a gH of 10 you'd have no problem using the membrane for a year, at least, as long as you remember to flush it well. My first one was a gift from a friend and had already been used, and I put a couple thousand gallons of water through it, easily.

Hope any of this helps at all and doesn't just confuse the situation more.

Barbie

NOTE I fixed the typo in the link, oops

[INXS]

Thanks Barbie, it's good to know I can always count on you

I couldn't get the link to work but I assume that it is the same as Marcus posted to my Q in Aquarium maintenence on Aquamojo.

Apparantly the units go for $68 (?) Do you know if the company ships to theUS?

So after getting that I should hope that I'll finally be able to get the L-177 , Rams and blue dempseys to survive and maybe get some of the plecos to breed.
Thanks again

[Barbie]

Oops, I'd made a typo in the link, I fixed it. The units I posted are a bit more expensive than the ones Marcus found, go figure They are in the US and have the TDS meters for reasonable also. I will probably still go with the company I found, when I get around to ordering one.

Barbie