Maximum drain flow through a 1 1/2"

[subman]

I just purchased my return pumps and now I'm starting to think it's too much flow for my drain to keep up with.

I bought 2 of these Rio 32hf
The flow is 1500gph at 4' head so I'm looking at 3000gph draining through a single 1 1/2 drain. I have another 1 1/2" for emergency and I don't want any flow returning through that.

I will have ball valves on the return lines so I can dial them back but was hoping to get maximum flow through these and avoid adding more powerheads.