[MikeM]

The last few days have been punctuated by different perspectives on algae. Over the past two months my pond has experienced tremendous increases in algae production due to receiving full sun most of the day, rather than being in full shade before the hurricanes took away the tree cover. A slight green tint to the water can be observed when a white bucket is filled with pond water, but only a slight tint. It is not noticeable when viewing the koi, at least to my eye. The algae that is thriving is the carpet algae covering all submerged surfaces with a nearly half-inch coat of green fur. Individual filaments break off as the koi graze it between feedings. And, they do not simply get a vegetable addition to their diet. Within the filaments are the larvae of midges and occasional bloodworms. I have always had an issue with the broken filaments lodging in the leaf net and matting in the skimmer, and it can gunk up the filters if not attended regularly, but it was possible to get by for a week if I had to be out of town. No longer. With full sun, the "algae glarf" is sufficiently copious to clog the leaf net in the skimmer within 36 hours. So, daily cleaning is essential to prevent a blocked skimmer and potentially a burned-out pump. I have increased water changes such that nitrate levels in the pond are below 10-15 ppm at all times ... the best I've ever done. [Never measurable ammonia or nitrite.] I will eventually shade the pond when I make up my mind on a new "grand scheme" for the garden. In the meantime, I view the algae as a bit of a hassle that I will live with. ... an inconvenience, but one I accept because the koi are doing well, eating well, and the water is healthy.

This past weekend our local koi club met at the home of a new member who has a pebble-bottomed water garden with a few goldfish and koi. The waterlillies were beautiful. I noticed that there was virtually no algae in the pond. The pebbles were relatively clean and the grand waterfall rocks were spotless. I assumed the owner had "cleaned up" for the club meeting. I was partially right. It seems the owner detests algae and uses a power wash sprayer regularly to get rid of it, as well as regular doses of algicides. The water was relatively clear, but had a greenish tint despite frequent application of algicides. The fish did not seem very happy.

During the get together, I mentioned my recent algae growth. Uniformly, I was given suggestions on how I might get rid of the algae. My comments were misunderstood. My quandary is not over how to get rid of algae. There are many ways to do that. My problem is finding the time to deal with the inconvenience until a shade structure is in place, because I do not want to get rid of the algae. I just want to slow it down. I cannot imagine a circumstance in which I would use an algicide.

On another board where I lurk, I have been reading complaints about new pond syndrome, green water and use of UV systems to gain control over the unicellular algae. The pond owners complaining do not have established biological filters. They are exasperated that they cannot fully enjoy the ponds they built in summer prior to the colder days of Autumn chasing them indoors. They are being advised on proper maintenance routines and the use of UV.

It is the nature of algae to grow wherever the conditions are proper for its success, and competition is not too great. With adequate biological filtration and oxygen levels, the unicellular algae will not interfere with koi rearing. It prefers ammonia as its source of nitrogen and declines as nitrifying bacteria become well-established and filamentous algae begin to populate the pond. I no longer use UV, because I do not find it necessary. I would never seek to remove algae from submerged surfaces or the rocks of a waterfall. I see the algae as nature's bio-cushion, with every filament filtering the water in complex ways not fully understood, supplying habitat for beneficial life forms and directly enriching the diet of the koi. I do not see it as an enemy, but as an allied element of the natural world ... one that can become mischievous when given the opportunity, but all in all, a friend of the pseudo-natural balance of the koi pond.