I use Aqua C Urchin Pro with a mag 3 and love it. Ken Koehler talked me into one sometime around 2002/03/04? It has been too long, but Richard from CB pets sold them so I bought one for my 200 and 158. Plug it in and it works, that simple. I have been on this website seeing post about high dollar skimmers having to be adjusted or not skimming, or other problems while my Urchin(which probably isn't large enough) keeps on working with no problems. I would think the Urchin Pro would be plenty big for your 45? Good luck on what ever you choose.