Gonna be a lot of flow for a 65 gallon tank. By itself, you will have really strong flow in some spots and dead zones in others. Although I hate that the WP-25 cost as much as the wp-40, two of the smaller ones would be the best option. Since you already have the Multiple Hydor pumps, you could very well go with a single WP-25 to give the tank a random flow then put all Hydor pumps in areas of the tank where they would not be seen, such as some in the back.
This would give you plenty of flow in the tank, some random flow and cover the dead-zones. With a wp-40, your tank would not be catching much of a break since the minimal flow is about 800 gph. The max flow is about 3400 gph which can be a bit much if you don't have plenty of open water to catch the flow. The smaller WP-25 puts out 1000-2100 GPH and is 1/3 the size. Much better option.
