Read, read, read! That being said, I agree with getting rid of the damsels. They are very territorial, aggressive little buggers. Every addition to your tank will be a threat to the damsels, and they will harass your additional fish to DEATH, literally.
You must get a test kit, preferably a kit with liquid tests and test tubes, as opposed to test strips. Start a log, recording your parameters. With a smallish 30 gallon FO tank, you should test every other day at minimum, as parameters will change rapidly in a small tank.
Rapids Pro filter system- I have been using this system on my 75 FOWLR for about 8 mos. now. Overall, I am happy with the system, with a few issues that must be addressed. I'll start at the overflow- it's a little tricky to get set correctly, but the adjustment screws make it easier. The Aqualifter pump is great, never have to worry about overflow due to power loss.It does not skim the surface of my 75 very well, but will probably work better on your 30. The protein skimmer takes a bit of trial and error to get the best performance, but once set it works quite well. I replaced the air pump that came with the system with an adjustable Luft pump, but this may not be necessary. Replace the wooden airstone at least once a month for maximum performance. Filter media- You will have to experiment to find the best combination of media for your system. I have a high bioload in my 75, so I ditched the bioballs and added a couple media bags with carbon. I also ditched the carbon filter pad and the carbon pillow in favor of cheaper loose carbon in media bags. I left the sintered glass cylinders in the lower media tray. As for the rated flow of this system- The pump supplied with the system is rated (along with most other pumps) at a horizontal, unobtructed flow. Therefore, if your filter is under your tank, with a 3-4 foot head, the pump is supplying only about half it's rated flow. I suggest you get some fitting from your LHS to split the flow from the return to maximize water movement in your tank.
Good luck, and welcome to SWF. There's volumes of useful info on this forum...Glean the information necessary, and don't take any responses too personally. Some people on here and other forums have been dispensing info to newbies for yaers, and get tired of the same old questions over and over....comes with the territory, but their responses come across as being sarcastic..... you gotta learn to deal with that.
There's a few stickies on every topic here.....read them all, you will probably garner enough info to have your 30 running beautifully in no time!
