| Akai-San, it's probably easier to keep clear water in areas without a severe winter. Without the seasonal cycles, the pond stays much more stable. On the mainland, it is common to get an algae bloom in the spring when things start to come back to life. To a lesser extent, that happens in Hawaii as well. Nelson mentioned that it happens to him but disappears pretty quickly. I get a light algae bloom when the monkey pod leaves fall and the sunlight increases in February-March. Otherwise, that pond is too shaded to keep a good carpet of algae on the sides of the pond so it cannot cope with the sudden influx of light.
I agree with Authur that a little green water does no serious harm and the only real danger is when it gets thick and then all dies at once due to chemical eradication or a natural population crash. Were it not for the koi observation issue, a little green water may actually be beneficial as it supports a food chain of forage items.
-steve hopkins |