If you do a web search "ultrasonic Algae control" for instance, you come across screeds of information. Spend some time working through it and a couple of themes arise.
I have found a couple of points of concern and a couple of contradictions. Certainly there seems to be something in the claims of Ultrasonics and pond Algae control.
The one major concern I have is the frequency. One article suggested that the best freq was 28Khz. Another found 15-21.5Khz the best range. So which is it. But I am mostly concerned that this range is still very much in the audible range of much of our marine life.
The next issue is what can be controlled. There are 27000 different species of algae and 47000 variations of that within the group. So far 5 types have been unaffected by ultrasonics. It seems that plants and fish
are unaffected. So what exactly is being controlled on a boat hull. Boat hull cleaning
would mean plant and
fish life (as in shellfish) would need to be affected. So there are some contradicting statements being given here. One of the companies involved in hull cleaning show a boat being lifted from the water
. Claims are that it has little growth. Well it looks just like my boat when it is hauled and I don't have a sonic device. The test really should have a "control" subject and the test subject. And the claim that there was no weed and shell growth except where the keel
was submerged in the Mud. But the boat hull was certainly covered in algae. So isn't that what the device is supposed to best at killing?
I don't know. To sum up, I think there maybe something in pond control with Ultrasonics. But I would love to talk to some pond people that have tested and used the product before I am convinced. As for boat control, there is just too much that doesn't add up. I am not going to say it won't work, but from my own knowledge of sound and from the contradictions I have read, and
the fact that the frequency is so low and in an audible band to marine life, I am not convinced at all.
On a slightly similar but different subject. I thought it terribly sad about the young whale they had to put down in Oz. It lost
it's mother while still suckling and was dying of starvation. One can only assume it's mother was most likely hit by a ship. This is becoming more common and I think a great deal could be done at not a lot of cost, in regards to some kind of Sonic device being placed in the bows of ships that send a sound out in front to warn Whales of a ship approaching.