So I am wanting to go saltwater here soon.

[SirRye]

My issue is what size tank I should start with I want something between 40 and 75 gals but I hate to get to big and find I just don’t like it or it’s to much trouble for me and my family to take care of.

Then what type of cleaner if I go with just a 40 gal would a hang on filter be good enough to I start adding corals?

If I do like it would add a sump tank though and add some cleaning there aswell though.

In advice would be awesome though.

[Sniperhank]

A HOB filter would be ok on a 30ish gallon as you are getting a feel for things. If corals is your goal, really ro/di water would be much more important so you have a pure start on all water going into the system.
I would look at a 20 long. Several reasons on this. It is a popular size of tank and it wouldn't take the strongest light source to keep some of the hardier starter corals. If you decided you really like going through saltwater, you can easily turn a 20 long into a sump for your equipment that one would have on a larger system like a protein skimmer, ATS, so on. Along with that, the smaller systems are easier to manage issues via large additional water changes on top of the 10% weekly water changes you'd want to do.

[SirRye]

Does anyone have a diy build list for a ro/di system? If I can build it I would like to go that route then buying a whole complete system

[Sniperhank]

I'd suggest getting one from bulkreefsupply or ebay. Mine from BRS was a great unit for the price.