Hey, thanks for noticing that I rock !

Keep checking your levels daily. An ammonia spike will kill those fish, which is not cool, even for damsels. Better idea to get rid of them now.

There have been lots of new and gently used Koralia powerheads in the "for sale" forum the past few days, so I'd recommend you check there. Koralias are inexpensive and convenient powerheads and a good option for you. Your 29g would do well with a K#2 or even a #3 probably (anybody with a 29g cube want to offer up what size they would recommend?). We tend to overkill on flow, and had 2 K#2's on our 20g hex in order to point one up to agitate the surface water, good oxygenation and keeps pH up then one pointed more downward and bouncing off the front glass to diffuse flow throughout the tank. Worked well for us, but considered overkill by most.

You cannot post in the for sale forums until you have had 50 posts or pay the $25 for a charter membership, but if you want to buy something in the for sale forums, you can just send the seller a pm about it.

There are also some hang-on-back skimmers and other inexpensive skimmers to look at in the for sale threads. Cannot recall if you have a sump to put a skimmer in, but if not, the hang-on-back (or HOB) is a good option for you.