Coping with the muck and the mire: the clean out
It is around about the end of July that it begins to become apparent that although the pond is perfectly healthy, everything in it has simply become overgrown. So perhaps it is not just a haircut required at the end of the season, but a thorough sort out is in order too.
October and the lily leaves are standing up which is a sign of being too shallow or overcrowded. The plants in the baskets have all linked up.
An investigative dredging with a net reveals more rubbish than was envisaged. Time for a cleanout.
Early October is the best time to do it before the frogs decide to call it the end of the season. Also it is an opportune time to check out that persistent drop in water level which you are sure is attributable a small hole somewhere. However if there is an obvious desperate need earlier in the year then needs must prevail.
If there are telltale bubbles of gas that emerge from the stygian depths of a gloomy pool with a mere casual nudge with a stick or net into the bottom mud, this spells emergency! And something must be done at once to avert disaster.
Of course its not your pool, its just a nightmare. You would have done something about it long before the mud at the bottom was even 3 or 4 inches deep. But when you see it elsewhere and you net up layers of detritus and leaves, rank with a foetid pong, you can confidently assert that it is time to clean the pool out NOW.
Every pool and pond in the whole world is filling up with muck from animals and rubbish from plant life all the time. In fact the whole world is, and unless there are any busy little helpmates to break up the rubbish into its constituent elements the environment, be it pool or countryside, would very quickly disappear under a heap of leaves and excrement. Ultimately it is bacteria on which we all depend and we have already mentioned the heroes Nitrosomonas and Nitrobacter that with a little help from friendly fungi, break up all the organic matter that falls to the bottom of a pool to chemicals that can be absorbed by the plants as fertilizer.
Bacteria are pretty much ubiquitous, but these particular friendly and useful ones need plenty of oxygen all the time in the process of breaking down the organic compounds. So if there is no oxygenating weed (I mean a lot) or there are no fountains, streams or waterfalls or if there is too much to process and they are stuck under 3 inches of unprocessed sludge, they die and are replaced by bacteria that work to the detriment of the habitat, allowing ammonia and related gases to build up that will poison the inhabitants, particularly the fish and especially Koi.
The result is there is the other warning sign; the fish gasping for air at the surface on close airless summer evenings. Get a water test kit and test for ammonia and possibly oxygen. Any reading at all on the ammonia test is an indication of a potential problem and the oxygen level will confirm that.