Well I wanted to chime in on the progress I have had using the Vortech pumps. As some already know, I had a tough time with these after the initial installation, but with theh help of Eco-Tech, Tim, Andy, et. al. I got new parts and drivers and have good news to report. Since adding the little washers sent out for thicker tank walls, my pumps have been very quiet. They will make noise only when they have been jarred which I have found may happen occassionally because of the tangs nipping at algae growing on the wet frames.
When I first had problems Tim asked me to leave them off my Neptune Controller so I had no control and was turning them up in the morning and down at night by hand. After about a month of that, we agreed that I would try one on a 5 min ON/5 min OFF cycle and see how that went. It did go well and now I have 3 pumps running full blast during the day and OFF at night and one pump cycles on for 5 min, then off for 5 min continuously.
Most importantly my corals love the flow from these pumps. Growth rates and PE have improved and color is very good. I had another reefer over today who asked me to sum it up much as I just did, and I told him I would buy more of them in '07.
I have to admit I still don't quite understand the 5 min rule when I see these pumps in videos pulsing on and off rather quickly. The MACNA video of the waves created by these pumps is awesome, but also clearly not on a 5 minute cycle.
Only one small negative to report at this point (aside from control issues) is that when I removed one of them this week to clean it, I found light crazing over 100% of the area where the pump was mounted. This is not earth shattering for me since no one will see this and my tank is 3/4" thick, but is does concern me that many tanks that will use these pumps have much thinner acrylic. I have never seen any over-heating error codes but the motors have felt quite hot as has been discussed in various MP40 threads.
I also checked into the FAQ tonight and see a recommendation that the drivers be mounted to metal to dissipate heat. I don't recall seeing this in the instructions but think it may be a good idea in my case. Right now I have them mounted to walls that are wood and coated with bilge paint, which I think is a bit insulative.
I can't wait to get the whole package set up!