type of water

hi, i'm new
i was wondering if anyone here who had reef tanks used regular tap water, RO water, or RO?DI water. And if so, do you guys have your own RO/DI unit or would you just get them at your lfs?

I've got my own RO unit but that's only because i add water on a daily basis. My nieghbor just goes to the LFS for water..

I've got an RO unit i need to sell if you want one...

I get a lot of **** for doing this, but I've aways used tap water straight from my bathtub and used Prime to clean it up. Prime dechlorinates, removes ammonia, and detoxifies nitrates and nitrites. It also says it provides a slime coat, but I also have little sample bottles of StressCoat from API that I add in every now and then to help my fish out. I'm sorry, I just can justify paying for water. I'd be broke in a week.

^ Saltwater or freshwater?

and its not bad depending on how expensive the corals are you're keeping and the phosphate reactor you have

I use RODI, but I used to buy saltwater from a LFS. As long as you're not having an algae issue, your corals aren't sensitive, and you don't have copper in your pipes, you might be able to get by with tap water.

My experience was that when I used to use tap water, I had a horrible hair algae outbreak. Also, while you can buy water from a LFS, be careful who you trust. I bought water from a store by my house until I found out that when they went to the back to fill up the jug, they were using water from a hose and not a RODI unit.

An RODI unit is expensive, but will save you money in the end. We happen to be raffling off two $25 coupons to Air, Water & Ice (a business that sells RODI units) at our raffle on Friday...

it's for a reef tank, and i plan on keeping montipora hard corals, juss wondering
what if you guys had a recommended rodi unit in mind

also, i don't plan on getting a phosphate reactor
instead, plan on using a rdsb on my sump along with some macroalagae and a protein skimmer

With sps you are going to want to use RODI water either from a store or a personal unit. I own an Optima Dual DI unit. It has four stages (micron sediment filter, carbon, di resin, and another di resin). Work great. I don't have a phosphate reactor, and I've never had a problem without one.

I've just always used tap water. The only problems I ever have with algae are currently my cyanobacteria (which is dying out now that I've started doing something about it rather than hoping my snail would eat it) and a hair algea that decided to take over a small shell I had in the corner, so I took it out, problem solved. I never thought to check if there was copper in the pipes, but since I've never had anything die from using tap water, I guess there isn't. And I've never had a phosphate reactor. All my corals seem fine with it, but I've never kept montipora

I've never tried tap, but +1 for RODI since I haven't had problems.