Like the new skimmer! I stick with the 'old school" skimmer technology on my systems. I actually have a few back-up skimmers that i rotate sometimes. Ive got two of the 6 foot dual downdraft ETSS commercial skimmers and a third similar model that was shipped USPS and arrived broken at every possible place. A dual beckett Precision Marine Bullet XL3/4 (Custom height with the dual beckett bullets). I also recently was able to find what looks to be an original model recirculating MTC that's over 5 feet as well. All of these skimmers require big pressure pumps which add to their cost and electric bill. But I believe that these trusty technologies like the injection, downdraft, beckett and recirculating have benefits that are unique and more ideal when processing 1000+ gallons and heavy bioloads.
As for the Mazuri shark/Ray gel, I definitely use it. I prefer it over the tabs, at this point. If I understand what their customer representative told me once is that with the gel.... large institutions and public aquariums order huge batches to be made but with unique vitamin, mineral, amino acids and different ingredients, that the biologists at whichever place have specified. The leftover gels from making these batches are what is sold to private aquarists. (I called them after receiving a jar that had said some alpha-numeric diet onot the label.)
When I makethe gel, I follow their written ingredients but I make the powder to water ratio much more in favor of powder, so that it comes out thicker. I use extremely hot water to mix it with and then i have a dish that is divided into four quarters that are about 4" × 4" each, and 1" thick. I bage each square seperate and freeze them. At first when feeding it to the sharks, they wouldn't touch. So then I incorporated the squares, cut up into cubes, in with their normal food that soaks in second or vitachem. That got them eating it. Now I can feed them the gel exclusively as long as I let it sit in whatever liquid supplement I'm using for a while.
Phew, that was long winded!