Top 5..or 10... MUST haves for a reef tank

[lastlight]

unless you're away from town for days your lighting timer failing on or off won't be a deal breaker... you'll notice. But temperature control is a must. If you don't want to rely on a fancy controller buy a ranco etc. $100 and you have bullet-proof temp control. other than that a tunze osmolator ATO like others have said.