Need skimmer advice

[FSU]

I finally got my 75g set up (pictures soon) and I am using a RS-100 Euro-reef skimmer. It doesn't seem to skim quite as good as it use to and isn't real loud, but does hum a bit. Lastly, I do notice that my water temp jumps up roughly 2-3 degrees with it running. I am wanting to upgrade to something newer and replace it, but not quite sure with what to get with all the newer ones out there. I am wanting something that I could use on a bigger tank in case of up sizing later, but not something that is ridiculously expensive. Lastly, I need something that's not real tall, as I am using an AGA tank and stand and there's not a whole lot of room height wise.

I appreciate any info and opinions, TIA

Rick