new to nano questions

[Snaz]

150w MH is a lot of light for that size tank. That said if you can get the temp swings under control and you "light aclimate" any new corals you should have a nice little tank for SPS.

If you go with a fan over the water surface for temperature solution you will be topping off once or maybe twice a day so an ATO is probably a must. As said above, nano-reef.com is a great resource for 30 gallons and under.