I'm thinking of upgrading my 10 gallon to a 30 gallon. Right now, I have:

2 Skirt Tetras (1 white and 1 black)
1 corydora (the little spotted kind with the black mask)
1 Bleeding Heart

I am definately going to get at least 2 more Bleeding Hearts and 1 more Skirt (hopefully a gold skirt). The Skirts right now are chewed to pieces (fins) so I think they are fighting. I wouldn't mind 1 more Cory either (I would love an albino) but worry that there would be too much competition for food (I do feed sinking brine pellets...though the Tetras usually try to grab them as they sink)

Any suggestions for what else to get? I'd like some more colorful fish. My ph is pretty high 7.5-8 and I don't like messing around with Ph. the water is also very hard by me.

Harlequin Rasboras look really cute and since they are small, I was thinking I could get 6 but not sure if they would be happy with nippy Skirts?

If I am calculating right, I would have room for about 14 inches more of fish once I get the skirts and bleeding hearts (calculated based on expected size):

3 Skirts * 2.3 inches = about 7 inches
3 Bleeding Hearts * 2.3 inches = about 7 inches
1 Cory = 2 inches

I think you need more than three skirt tetras to stop them from fighting.

nippy fish need to be in groups of at least 6. the bleeding heart 4 and corys like at least 3 to feel happy.

Wow, so sounds like I need to go even bigger than 30 if I want to introduce a new species...I'll have to measure the area to see just how big I can go!

Question about the skirts....does it matter what color? ie do all 6 have to be Black Skirts? Or can I mix the white, gold and black?

Of the 3 (skirts, bleeding hearts, cories (I assume not the cories since there won't be junk on the bottom yet) , which are my hardy to cycle the tank with? Should I dump all of the same type in at the same time (merge the new ones that will be in QT with the old ones that are currently in the 10 gallon)?

I wouldnt use any tetras or corys to cycle a tank as they are quite delicate. Could you do it fishless with either ammonia or flake food?
I used a shubunkin to cycle my first tropical tank and kept him after.
tetras will mingle with any other tetra really and they dont mind if they are black or white.
you wont need to add them all together as they will readily shoal with newcomers.

I was going to leave the tank fishless for a couple of weeks before adding fish but then figured I wouldn't want to add everyone at one time after that? How do I cycle with fishfood? And would I use the tropical flakes or does frozen brine work as well (does one work better than another)?

I also have the product Cycle at home...does that work? I heard Biospera is good but I have never been able to find it around me.