I have a goldfish pond that I built about 12 years ago. It's roughly 1000 gallons, 3' deep, and has a waterfall that's about 4' above the surface of the water.

I put in a handful of goldfish in the beginning, and they've bred unregulated so there's God-only-knows-how-many in there now.

I USED to have pickerel rush in there, but it grows so fast that 2 stems two years ago completely dominated the pond this year! I pulled it all out but for 1 stem, and I'm really not that upset if it doesn't come back.

I used to have 2 pond lilies in there, but they didn't come up this year so either the rush killed them, or maybe they'll come up next year. I also have floating parrot's feather.

It's also worth mentioning that there are plenty of trees around, so it get leaves in it. I try hard to prevent it, but... it happens.

The problem I have is the water clarity. It has NEVER been all that clear, you can see about 6" under the surface but that's all. I wanted to install a water bog filtration this year, but... time and money, ya know.

I'm having a hard time determining the size that the pump should be. I currently have a Jebao JGP-8000 pump, rated at 2,100gph. I thought that was enough, but after accounting for head height and everything I'm not sure. And if it's too small, that would certainly explain the lack of water clarity.

How big should the pump really be?