Microblift has this to say about feeding in the hot weather:

“What Should I Do Now?

August is traditionally the hottest summer month.  If possible, shade the fish pond.  If that is not possible, shade the filter.  This will provide some measure of relief from the heat.  A hobbyist told me she adds blocks of ice to her pond.  I don’t think that’s a good idea.  In fact, I think that might be very stressful to the fish, more so than being subjected to the warmer water.  Doing partial water changes is helpful, adding the water slowly the pond to cool it gently.  Sudden temperature changes are never desirable.  Continue adding PL (or HC in ponds over 10,000 gal) and Barley Straw Extract (or Pellets). But if the water is above 75F, stop using Sludge Away and don’t use any algaecides until the weather cools down.  If the algae problem is so bad that you have to do something, do it manually.  If water temps reach 90F, stop feeding!”

Link to beneficial bacteria: http://shop.funkykoi.com/category-s/99.htm

Link to water treatments: http://shop.funkykoi.com/category-s/47.htm

Link to pond thermometer (free with first online order): http://shop.funkykoi.com/Laguna-Pond-Thermometer-p/pt945.htm