[PortWash]

Hi all, I have a 180g tank, the fish store just wont let me take it home till I pay for it. I am looking to set it up as a FOWLR tank. I have been reading as much as possible. The marine set up is rather intemidating as there are far more things to consider than my current freshwater. The first of the questions that I have gathered is with regard to the protein skimmer. Would a hang on like Aqua C w. Mag 3 be sufficient? I understand that there are far more powerful skimmers that are in SUMP. However, I was hoping to not have to use a SUMP. Are under the cabinet skimmers their own category or is that still an in sump? With a good skimmer and mutliple powerheads would i still need a mechanical filter?
RO/DI water With 180g tank purchasing water doesnt seem like a long term option. Could I purchase Carbon and DIY a filter for my tap? (Sorry the test kit hasnt come yet so no tap parameters) I am also planning on smaller more frequent water changes as I live in a studio apt in NYC so space is of the essence. especially with a 180g and 55g tank. Do you constantly havea batch of salt mizing for top offs or can you just add RO/DI water without salt mixed for top off?
Those are my primary areas of concern(thus far), I am more than certain that these will be far from the last as I havent even begun to look at anything fish related.
Any input is very much appreciated.

[leebca]

WELCOME TO REEFLAND!

You've come to the right place for information. AND you have made a great decision to plan what you are going to do -- in advance. Take your time.

Your questions do show that you have not done a lot of reading of what is already here on the Forum for you. So, if you don't mind, I suggest you read the following posts for information and then ask questions:

Setting Up a FOWLR Aquarium

WATER - Source and NSW

How to Make a Successful Water Change

What is Water Quality

Regarding your questions:
A FOWLR system creates a lot of nitrogen waste (a lot of organic pollution which a powerful skimmer is almost essential). A sump is your best bet for the skimmer. Skimmer size and recommendation is given in the last link above.

The water you speak about is what we call "source water." The above link will give information on that.

In addition to the above, you might want to look over articles and other posts here relative to the hobby. If you go to this one link, it lists other links and references posts and articles of different marine system topics:
Table/Contents - Link List

The weight of that large of marine system is considerable. You mention living in an apartment. If you are not on the ground floor, be sure the apartment structure will support the weight.

I hope you like to read. If you'll take time to read and plan, you'll have an easy time with this hobby! I suggest you do the reading and then ask about anything that isn't clear or explained well enough. We are here to help!

Water mixing and information for making water changes are given in the next-to-last link above.

[PortWash]

Will read more then come back. Thanks Regards