I am looking at getting back into this after many years absence. MANY years! One of my LPS will have a used Red Sea 250 with cabinet, sump & lights available as a trade in next week for $800. Also includes sand and rock. He thinks it’s about 2 years old. A customer of his is trading it in on a bigger Waterbox. So my question is - is this a good deal and what questions should I ask and what should I look out for?