The salesman doesn't know what he's talking about. Very few of us on here keep our tanks that cool. Mine stay at about 80* and creep up to 82* during the summer. Some folks keep their tanks at 84* all the time. Remember, the fish and corals are from tropical waters and are used to warm water. The only thing you'll need to monitor is how much heat your lights and pumps add to the tank during the course of the day. Once you have that balanced out, everything should be fine. I very much doubt you'll need a chiller.
The Aqua C Remora should do a great job on a 38 gal
tank. I would get it with the Maxi Jet pump and I'd recommend adding a surface skimmer to it. That will not only increase the efficiency of the skimmer, but will help with microbubbles being returned to the tank.
Assuming you'll have at least 1.5lbs per gallon of LR
(2 lbs per gal
would be better), you won't need any other filtration. A wet/dry is certainly a valid option for a SW
tank, but you really don't want one on a reef because there are natural ways to handle the biological filtration. These are usually used on FO
setups where there is no LR
or on FOWLR
tanks that house fish that are heavy waste producers. If you'll go with a DSB
when you set up the tank, you'll not only increase the diversity of life in the tank, but you'll also have a natural way to get rid of those pesky nitrates. I would take the money I would have spent on a wet/dry and invest in several powerheads and a wavemaker. This will help you create a more natural reef like environment for your animals.