Hi fellow fish fanatics, hope you all had a Merry Christmas.

I've had my vertex double disk airstaion going since mid November in my 20 foot deep 1/2 acre dugout that flooded in 2010 to become a 6 acre pond with maximum depths in the flooded region being 8 feet.

I set up the airstation this year in 10 feet of water within my dugout and about 20 feet from the spoil pile from the dugout. Aeration opened up a nice 45 foot wide hole in the ice which provided lots of open water for a nice distance over the dugout.

Unknowingly the hose froze up to my airstation last week and come the weekend about 4 inches of clear ice had formed where the water had been open. Upon checking this area out I was disappointed to find 4 dead 3-4 inch long perch in the shallows above the spoil pile and adjacent to the much deeper water of the dugout. I am hoping that the deeper water hasn't been depleted of d.o. but am at a loss as to why these fish wouldn't seek refuge there? What have your experiences been in this type of situation?

My plans include acquiring a d.o. tester so that I can monitor my water, any particular brand/model preferred that doesn't cost a small fortune?

Fortunately I got my airstation going and installed a second unit for good measure. Now I need to keep a closer eye on them during the week.

Thanks for any advice you can provide!