which one i need filter or skimmer?

[Leah]

I have a 25gal reef tank it has 2 large colt corals, sponge, mushrooms, plate corals, pulsing xenia, large leather coral, bubble coral I think that is it for corals. I have a firefish and two
zebra dartfish, 2 cleaner shrimp, pom-pom crab, hermits and a couple snails. I have a aquaclear 70 filter on it and do not use a skimmer. I just do a weekly water change approx 2 gals or so.

Leah