Warm Water and Oxygen In Ponds

Western Europe has experienced record temperature levels and a number of people have reported gasping fish. I anticipate that our South African summer will also be like this based upon the last few days in Johannesburg so I thought I would once again bang my oxygen drum. You will know by now my belief that any pond should contain 3 things .... water, oxygen and fish.

When water temperatures are high as they have been then a serious reduction of oxygen levels takes place in any water course for the simple unavoidable reason that water dissolves less oxygen as water temperatures increase. You can only do your best to compensate for this by ensuring your waterfall is working and that you also run a spray-type fountain. Of course if you have an air pump and air stones then keep the air pump running morning, noon and night.

Water at 25 degrees C can hold only 89% of the oxygen that water at 20 degrees can hold. At 30 degrees oxygen is depleted by about 20%. This is a great deal when seen from the perspective of the the fish and the bacteria in your biofilter. In fact because dissolved oxygen content is lower the biofilter works less well which creates more of a strain on the pond system.

At higher land elevations as in large parts of South Africa, and in places like the Rockies the problem is made even worse because oxygen concentrations are also influenced by air pressure. At about 5,000 feet above sea level water holds about 8% less oxygen than at sea level.

As I have said many times you cannot add too much oxygen to your pond. Waterfalls are essential I believe in any pond.