@dahenley - When it comes to equipment, there are no real secrets to be told. We run skimmers, pumps, lights (for us, not the corals), and Ca reactors. I am an early adopter of a lot of equipment, so there were a lot of purchases "to see what it was like." That is why in our systems you see three or four different types of skimmer.
So first talking about those skimmers, I've come up with a couple of preferences. So far, I've used the RK2, Lifereef VS3-60, ReefOctopus 5000sss and 6000sss, Custom GEO, Bubble King Supermarin 250, and Orca 250. The first is I am not a big fan of external skimmers. The RK2, Orca 250 and Lifereef skimmer were external. If for some reason there is a leak or overflow, there will be a considerable mess to clean up. If this happened with an internal skimmer, it just goes back into the sump. Also, the RK2 and Orca 250 used an external pump with seals and those seals are guaranteed to leak after a while. If I had to do it all over, I would probably go with large internal skimmers.
The second observation I've made is acrylic bodies and greenhouses don't mix. Acrylic is pretty and all, but it will grow heaps of algae in direct sun. The GEO and RK2 have solid colored bodies, and pretty much stay clean even after years of use. This is also why I cover the calcium reactors. They would clog with algae growth if left uncovered, and that includes the bubble counter.
Lastly, I appreciate skimmers that can be taken apart easily and soaked in vinegar. Some of the space-saver designs are great if you have limited space in a sump, but in a greenhouse setup where space is more abundant, you want easy access to all the individual components for maintenance.
As for multi-pump vs. single pump, I am all about single pump. I personally would not buy a skimmer that required more than 2 pumps (1 feed, 1 recirculating) if I could avoid it. Reef systems have a tendency to turn into snake pits of wires and I try like heck to avoid it. When I first started this greenhouse, each 1,000 gallon system literally ran off of THREE outlets each. Since then, lights and other gadgets were introduced, but I still try to cut down on the number of devices to not only save on electricity, but to save on clutter.
Other than that, I try different things in hopes of improving the system. Sometimes they work out, sometimes not so much, but at least I have first-hand knowledge going forward. Recently, the issue I ran into was a lot of newer products are manufactured and assembled in China and there is a major drop-off in quality. I realize that it's hard to avoid Chinese manufacture these days, but right now they are on par with Japanese and Taiwanese manufacturers in the early 80's (which is on the wrong side of horrible). Unfortunately, it is something I have to pay closer attention to now when I pick out new toys.
