Hi Keith,
You didn't mention if you were going to have foams in your AC 500s. If you do, you MUST clean the living heck out of them weekly. Even if you are just using carbon in the AC 500s, a lot of detritus will collect on the bags, and they will also definitely have to be cleaned weekly.
Actaully, weekly maintence in any tank should be a must, IMO. That will include a water change, filter cleaning, and testing and adjusting alk, Ca and Mg. Here is a page on
Reef Chemistry, which is a very important aspect of reefkeeping whenever corals are added to a tank. Read and reread the information, like I have to do, in order to understand the complexities of the chemistry in a reef.
HTH
