I thought at one time Laguna had stainless steel balls but could be wrong. I got some of my stainless steel balls from a local pet store and the rest from garden centers around town. Have not seen any lately for sale around town.
So cold again tonight. Looks like another -30 possible tonight. Front yard guppy pond all covered and snowed in. Topped up the water in that pond the other day. Seens to be running well this year dispite the extreme cold. We shall see come spring if any left over guppies still alive out there. Water felt warm last time I checked.
The main Koi ponds all running good and no ice under the cold frames (except bottom pond shallow edge had some ice around far edge of pond) dispite the extreme cold. Big koi looked lively and warm today under their coldframes and blast of warm air feels good when you peek under coldframes, from just one 1500 heater heater that is heating all four big ponds. Sure glad I put the cold frames over top. I used to be able to run all three ponds with just one heater, without covering ponds, but after I added that new deeper pond about 4 years ago, the heater struggled to keep all ponds warm so now I cover them and everything runs really well now.