Filter system for small garden ponds

[poconojoe]

I started paying attention as the air temps went up and down as to what it did to the water temperature, years ago. I have a temperature probe in the water which transmits to my davis weather station. I get real time readings.
A cold night would drive the temperature right down. Mine does have a lot of surface area. A hot sunny day would bring it up. But even with full sun in the summer, heat in the 90's the pond never jumped over 85 or so. Then again mid summer the bog is FULL of plants so the water is pretty shaded, now that I think of it.

Thanks for the analysis.
I think I was getting a bit paranoid!
I went out and looked this morning and can see there's less water above the gravel than I thought. There are some spots where it's below the gravel. Where it's above the gravel it might be just 1/2", maybe an inch in some spots.
Winter paranoia...I guess...