445nm Laser Project.

[Giovanni]

A friend and I have always battled with aiptasia. We have tried many kinds of control, aiptasia x, etc. They always come back and sometimes with a vengeance. Recently we discovered that some people were using 445nm lasers in the 1.8watt power to kill the aiptasia. After reading many threads on the pros and cons, I decided to give it a try. Only problem moving forward was finding a quality laser kit for a good price as most cost $250 and up. Recently I found a laser kit that sell for about half that so I decided to give it a try.

Here is my progress and thoughts.

SAFETY! SAFETY! SAFETY!

This is not intended to be a comprehensive guide to laser safety. You need to research the use of a laser and be responsible for your own safety. Here is a thread with a lot of good information "Use of Lasers in Controlling Pest Algae and Corals" . Please read as much of that thread as you can. It will help you be more safe.

I was hesitant to get one for fear being blinded, blinding someone else or my livestock. I live in an area of the country were handling firearms is learned at a young age. So after reading all the safety issue decided it was much like handling a firearm. The laser it the firearm and the batteries are the ammunition. Safety goggles of the proper type for the specific color of laser must be worn anytime the batteries are in the laser. Also the batteries and laser should be stored separate to keep kids from playing with them and harming themselves. I keep mine in a pistole case in the same place as I do my pistoles and ammunition. There is one more precaution that must be observed and that is being carful of reflective surfaces because the laser can reflect off things like glass and cause damage to surrounding people or objects. Anyone in the room must have goggles on.

In my experience when the laser reflects some of the light off my tank glass it is scattered enough and not focused enough to "burn" you or anything else. I will post a video demonstrating this. However this reflected light will cause serious damage to your eyes if you do not have the goggles on. Also if you do not have the goggles on and look at the end point of the laser it will cause damage to your eyes the same way looking at a welder's arc will. So combining the safety of guns, welding and reflective surfaces you can use the laser safely.

As for the livestock being harmed, The best way to protect them is to use the laser at night when the fish are sleeping. I have also observed that the fish are afraid of the light. Another trick is to place a foreign object like a fish net close to the area you are killing pest and the fish will avoid it same as when you try to catch them. If all else fails keep you finger on the button and if they come close discontinue use.

[Giovanni]

ANATOMY:

The laser has several parts. The safety goggles, laser lens, heat sink, laser Diode (LED), driver circuit, host, and batteries. The diode and driver circuit is housed in the heat sink. The heat sink and batteries house are housed in the host. In this case the host is a converted LED flashlight. I mentioned the goggles because safety first. The batteries power the laser driver circuit. The driver circuit provides a steady current and voltage to the laser which creates a large amount of heat.

The Kit as it come from the maker. It does require some simple assembly.



The Heat sink in this kit came with the laser diode installed.



This photo shows the driver circuit in the other end of the heat sink.



Here we have the Lens with a focus ring adapter on the end. The black part is the focus ring adaptor.



Her it is assembled.

[Giovanni]

USE:

The laser operates much the same way as a flashlight. The on off switch is on the back. Like many modern flashlights you can focus the light in a broad or tight beam. The light the laser diode emits is of one frequency 445nm but is not focused. The lens on the business end sets the focal distance. If the laser is not focused it will not burn your target. I practiced on a piece of cardboard. This focus depth is only good for burning an few inches. This is good and bad. The good, outside that focus zone and the light is to scattered to burn things you don't want burned, just watch the 3rd video. The bad, you have to have the focus point set properly to burn and kill your pest, watch the 4th video for an example of this. I like to shine the laser through my tank, the debris floating in the water coulomb is illuminated showing me where the focal point is. I can adjust from there. Often it is necessary to move the laser away or toward the target to get it burn a little faster.

Here is a photo of the laser beam traveling through my nano. You can see how the beam narrows then starts to widen out. The most narrow part of the beam is the hottest. This photo was taken from the 2nd video where I eliminate an unwanted nudibranch. He is just below the Laser beam.



The laser diode generates a great deal of heat. The heat sink and host pull that heat away from the laser but not fast enough to run the laser for more the 60 seconds. For this reason a 50/50 on/off duty cycle is required with a max on time of 60 seconds. Large aiptasia often require two to three sessions. Small ones can be taken care of in 10-30 seconds. It is also advantageous to turn all circulation pumps off. The theory is that the cooling of the circulating water make is take longer to heat the target. At a minimum it allows you to see bits of tissue floating to the surface. I am not sure it is needed because I think that the laser heats the inside of the cells of the target causing the fluid inside the cell to boil and the cell to explode. In that case it would not matter. I will be testing this theory later. Often with large aiptasia it is advantageous to use a turkey baster to suck the carcass off the rock. I start at the mouth and once it stops reacting to the laser, move on the the foot. Once you burn the foot enough you can suck it off the the turkey baster. If you leave any living tissue to float away, I fear it will propagate more some other place in the tank. many of the small ones burn enough that you cannot find anything left.

Subscribe and stay tuned as more is to come!

[Giovanni]

Video #1

This aiptasia was as big as I have ever seen about 1 to 1.5 inches across the disk. It took about 2.5 minutes of laser time to get him.

[Giovanni]

Video #2

In this video the nudibranch meets his demise.

[Giovanni]

Video #3

Here you can see that the 445nm laser is reflecting of the aquarium glass and hitting the arm. The beam is jot focused and only a small percentage of the light is reflected. The end result is that it will not burn you. Your mileage may vary. The laser operator in this video was not aware the beam was hitting his arm. However, it would still be dangerous to your eyes. Always wear the appropriate googles!

[Giovanni]

Video #4

Here is an example where the laser was focused so that the most narrow part of the beam was not far enough to reach the intended target. Moving the laser closer was not an option because of the aquarium glass.

[ReeferBatman]

Cool stuff...

[LeLutinBanni]

It took about 2.5 minutes of laser time to get him.

It's very long ?!

[Giovanni]

Originally Posted by LeLutinBanni

It's very long ?!

That would be the longest it should take. Smaller ones take less.

[jasonrstewart79]

Originally Posted by LeLutinBanni

It's very long ?!

Thats what she said.

Couldn't resist, sorry lol.

Seriously though, this is a great idea.

[Timber77]

Curious how far in can you effectively use this.....I almost want atipsia so i can have the cool lazer.... very cool.!!

[Giovanni]

It will focus and burn from across the room. If you decide you want one let me know.

[Ron Reefman]

I was the original poster for the idea of using a laser on aiptasia.
http://www.reefcentral.com/forums/sh...ighlight=laser
I currently own a 1.4w laser and use it. HOWEVER, they are NOT as effective as I once believed. I have found that if a small aiptasia is 'burned down' and the foot destroyed (which takes some serious time ... a couple of minutes) USUALLY they don't come back. Large aiptasia are almost impossible to completely destroy and will grow back. I've found that if lasered every day for 3 to 5 days, even big ones can be destroyed. But this is a slow process.

And three big factors are how much water you have to shoot thru, how 'clean' your water is and how much you can reduce water flow. Giovanni states, "It will focus and burn from across the room." And he's right. HOWEVER, that is thru the air and not thru water. Even clean tanks have far more 'stuff' in the water that will scatter the light and impare the strenght of the laser. I've been able to burn aiptasia thru a 2' thick tank, but it is far less effective and it normally will regrow. The other factor is water flow. The laser is heating the water in and around the aiptasia in order to 'cook it'. If you have much flow in the water and are working on the trunk of a bigger aiptasia, heat loss due to water flow past the anemone will at least slow the process down considerable and may make it ineffective.

So what I'm saying is that lasers have a use and can be effective, but don't consider them the panacea that will solve all your problems. They are expensive. 1w lasers are barely effective, 1.5w lasers are better, Giovanni's 2w laser is better yet and more expensive! And they are time consumming, especially if you have a lot of aiptasia or majano nems. They also have a fairly limited use time. The heat sink is small and overheating the laser can cause damage. Typical usable time for me is about 3-5 minutes, then I pull the batteries and put the laser in the refrigerator to chill for a couple of minutes. Pull it out , re-install the batteries and go back to work. It's annoying enough that I have 2 lasers so I can switch back & forth. So yes, lasers work, but they are NOT 100% effective and they have some real drawbacks. They are not for everybody.

[Giovanni]

I have experienced the large ones coming back also. This it remedied by using a syringe to suck them off the rock. If you laser the base it will release. The idea is to remove all the large ones. The small can be killed easily with the 2watt laser. You will never get rid of them completely but it is very easy to pull the laser out and remove a small one that pops up from time to time. Also I have not experienced the repopulation boom that often comes with other methods of control.

I have a source for 1.8 to 2watt lasers for $150 shipped. Subject to availability. As for the duty cycle of the laser. I can get them built into a computer heat sink with fan extending the duty cycle to almost unlimited.