Yesterday I poured a 9ft x 9ft x 5 inch slab and I am wondering if spraying the slab with water is better than using cure and seal during the curing process. I have also seen some people build a small dam around the slab to hold an inch or so of water. Which is the best way? Thanks.
All of those methods do the same thing.
The sealant method is done one time, no additional sealant needed.
The water spray method needs to be done regularly, maybe every hour or so. The dam method has time involved for making the dam, but does not need to be maintained as much as water spray.
All these methods are done only after the last troweling is done and the surface will not be disturbed by anything placed on top of the concrete.
Sealants are often used to reduce the maintenance requirement for fresh concrete (by municipal crews, for example). They're imperfect, though, so in hot, dry weather the curing concrete can still suffer moisture deficiency.
For that reason, regular misting is a marginally more reliable approach (assuming you're available to do so). It's also easier (no equipment or cleanup required) and cheaper.