I am going to start a refugium so I could get a Mandarin. Is it possible to just use a 5 gallon tank with a heater and a small filter that is not attached to my display tank? Do I need a filter? I was just going to get some Caleurpa from my LFS and throw that in the 5 gallon. There is already visible copepods in the caluerpa. What should the temp. be and do I need to feed them? Thanks