I am not really new to this site I was here late last year asking a question about filters and I purchased an Eheim and it works really well. No problems as a matter of fact with this new filter my fish keep having babies. My new question is what air pump do you recommend? I have a Rena and it does not pump enough air. I have a 30 gallon tank, but will be upgrading soon to a 40-50 gallon tank. Any suggestions???