Filteration question

[Scarlet knight]

I have a 29 gallon freshwater tank, running a undergravel filter with 1 aquaclear powerhead. I was going to run a whisper 2 HOB filter in parallel, but when reading the suggestions on the forum site, it seems that Aquaclear HOB is a more popular selection. So, I ditched the Whisper 2, and now I am running a aquaclear 300. It currently is running with the big foam filter insert. My question is, what is the preferred or recommended filter media I should be running in the aquaclear 300? Suggestions/advice welcome-

 

[BigJim]

I've got an AC70 aka AC300 on my 29g all by itself and the tank is crystal clear. I run the sponge and two bags of biomedia. One bag of biomedia is sufficient, but it's nice to be able to seed an tank with the second bag whenever I need it.