My daughter lives on an inner city canal system HOA in North Texas and they are having problems with a severe algae bloom. I'm looking for any suggestions that I can present to them to see if we can get the algae under control. There have been previous solutions with only short-term results. The algae has started to kill small Sunfish/Blue Gill. She has attended an HOA meeting where they discussed in the past how they have used Tilapia (downfall is they die in the winter), they have paid companies to come in and use chemicals to try and kill off the algae. Looking to reach out and see if you all would hav e any suggestions that I can pass along to her.
Yes, Tilapia die off in winter...but the effect of chemicals on algae "dies off" within weeks of administering it...and you have to repeat, repeat, repeat. To me Tilapia is a far superior control agent.
The problem is due to excess nutrients in the water. Remove those nutrients and presto no problem. However that is much easier said than done. Lawn fertilization run off is a huge contributor....but the probability of you or anyone stopping that is virtually zero.
Meadowlark is right on the money. It is excess nutrients probably from lawns. The majority of freshwater systems are phosphorus limited, meaning that algal growth is limited by the amount of phosphorus. They also consume nitrogen but there is probably too much of that in the system to control especially where lawns are concerned. One methods that has been used with some long-term success is the use of alum. Alum binds soluble phosphorus and creates an insoluble aluminum phosphate that settles to the bottom and cannot be used by algae. It can also improve water clarity. it can be applied directly or alum block can be placed where the water flows in. I don`t know how cost effective it is though.