So, I will soon be setting up two new systems in the lab: 1. A roughly 350 gallon tank, plus sumps, etc. 2. A six tank system (plus sumps) consisting of three roughly 90 gallon tanks, and three roughly 60 gallon tanks - so, total gallons of tanks (not counting sumps) = approx 450 gallons total. Multiple people have convinced me to go with external pumps, and I plan to have two, redundant, identical Japanese Iwaki pumps on each system, each pump on a separate circuit to guard agains total loss of flow if a breaker or GFCI trips. I'm thinking of going with the roughly 1500 GPH model of Iwaki pump - two of these per system. What are your thoughts on this flow rate? Is this enough flow? Or is this more than you would use? And why? (I'm guessing this is more GPH per system than what many folks here might use, but I like a lot of flow from return pumps.) Thanks.