Need help:I painted cement floor & now need to seal it
Firstly, why do you need to "seal" the floor? Paint itself is a sealer. If the coating isn't durable enough, the solution is usually more paint (of a high quality), not the application of a clear coating. I guess if you used wall paint on the floor, you would need to do something, but a quality floor paint should not need additional product.
However, if you must do something to the floor, get yourself to an actual paint store (NOT BigBox) and ask the folks there, who usually know waaaayyy more about paint than the guy behind the counter at BigBox.