25 gallon questions

[skabooya]

Yes 25gals is a nano. Speaking from personal experience 1 bulb wont be enough. You will need at least 2 T5 bulbs over that tank. Over my 28gal long I had 2x39T5HO bulbs... Is yours a High output T5 or normal T5? Anyway, I had 2 bulbs over mine and I could only keep softies and some lps. The lps had to be high in the tank close to the light.
I am almost sure nems need more lighting. Everything else should be fine with 2 bulbs. The galaxy coral may or may not be happy. LPS can be touch and go unless high up close to the light in a system like that.

An HOB wont provide enough flow. I asked about that before because thats what I was going to do. You will need a powerhead for more flow.

Invest in a skimmer unless you are definitely doing religious WC's

Pretty much everything is the same as a larger tank but you just need to be more careful as things happen much faster in a smaller system than in a bigger system. It takes a lot to keep it stable compared to a larger system.

[bignose]

I would go with a 4 bulb T5HO for flexibility with color.