I like your thinking on the additional pump to move more water this summer. Going in to winter with higher dissolved oxygen in the pond may help.

I worked up above 9000' feet today. Snow is nearly gone-only small piles on the north side of some buildings and in drifts alongside the roads.

We're expecting a couple of 80+ degree days this week down here at 6500'. Hopefully your pond will see 60s or even 70. It felt hot in the sun today at 9000+.