Use of Lasers in Controlling Pest Algae and Corals

[CalmSeasQuest]

I've been doing some research on the use of Laser light in eradicating and/or controlling certain pests frequent in marine aquaria. These include,

• Aiptasia / Mojano
• Blue/Green Algae including Valonia and Bryopsis
• Xenia
• GSP
• Virtually any other unwanted pests such as vermetid snails, predatory crabs...

In theory, it should be a simply process to eliminate any unwanted life from an aquarium, and easily prune others (think of it as a lawn edger for an area of Xenia or GSP.) I'm also curious about the possibility of using Laser to "cauterize" part of a coral subject to RTN. It might also work well for laser-fragging soft corals such as Z&Ps as it could be done while the coral was still in the water.

The most common laser pointers (< 5mW) do not generate anywhere near enough energy to be effective. Higher power lasers are now available that can emit enough energy to instantly "boil" the targeted pest, while avoiding damage to adjecent corals. The primary challenges with this approach,

• Cost - Higher power lasers are expensive.
• Safety - Eye protection is an absolute nesessity as intant blindness is possible should the beam (or potentially a reflection) strike your eye.
• Legality - There are FDA imposed restrictions on the sale of Class IV lasers (>50mW) that make them difficult (read expensive) to acquire.
• Risk to livestock - Caution will have to be maintained to prevent fish from being struck by the laser. At very high power settings, even viewing the point being lased "might" result in damage to their eyesight (still investigating this concern.)

I've ordered the components to build a 1800mW / 445nm laser to test the above theories and develop effective practices. Here's what the components look like (you can't purchase pre-built due to FDA regs)...

The next challenge is safety (mine as well as that of the livestock.) At this power output, blinding could be instantaneous if shined in ones eye (including a reflection of the beam.) Even looking at the beam endpoint unprotected is dangerous. Safety goggles provide user/viewer protection. I'm still working on a shield to prevent injury to livestock.

This idea was suggested by Lotus-Darkrose, a user in the Laser Pointer forums - albeit a bit difficult to deploy

 

[CalmSeasQuest]

I received and assembled the laser and waited for the batteries to charge (about 5 hours.) This model is 1800mW and generates a 445nm beam (beam is blue in color.) It has a 60 seconds maximum duty cycle and then requires a 120 second cooling time. I purchased a Pelican case and lock to prevent any unintentional access.

The second laser shown is a lower output 30mW laser with a 532nm beam (green.) This will be affixed to the main laser used for targeting and to test if any reflections will occur. The spectrum is important as the safety glasses block virtually all light in the 190-445nm range, making it almost impossible to see any reflections from the main laser. The green color beam of the targeting laser is easily viewable with the safety glasses on. Targeting with the low power laser is also important due to how quickly the main laser damages anything it touches. You would not want to hit a prized coral for even a second.

I've only had a time to conduct a few tests as I want to complete fabricating a shield to protect the livestock before continuing. Also, more time will be needed to fully determine the impact and to see if anything re-grows "“ but here is what I've observed so far"¦

Safety observations"¦This thing is scary-powerful. You have to be very careful.

• An 1800mW laser beam is both terrifying and amazing. I used a cardboard box to initially set the lens focus. The very instant the end point was focused, it began cutting through the box. In just a couple seconds the beam had completely burned through the cardboard.
• The Eagle Pair safety glasses do a great job of blocking light in the 190-540nm spectrum "“ All that is visible is an orange, pinpoint glow at the beam endpoint. Reflections are very difficult to see. This poses an additional risk and underscores the importance of first targeting with a low power laser (in a spectrum that can be seen while wearing the safety glasses) to test for dangerous reflections. It's also important to note that the glasses are designed to prevent against stray, reflected laser light "“ they are not designed to protect against a beam hitting you directly in the eye. After seeing the power of this, I shudder to think what would happen to your eye.
• Caution is advised is determining the angle at which you lase through the glass or acrylic. You have to be careful not to use the laser perfectly perpendicular to the glass/acrylic as unseen reflections will result in lasing your hand. Even the reflection is quite painful and feels like being stuck with a thousand needles. I now wear a long sleeve shirt and nitrile gloves when using the laser as another precaution.
• I have real concerns about any fish viewing the beam endpoint. Thus far, I've only used the laser in areas where no fish were present until I can fabricate a shield. I would NOT use this without a method to prevent livestock from viewing the beam end-point.
• Even after extended laser sessions with the beam in the same spot, I detected no temperature increase in either glass or acrylic. I made sure all panes were clean. As far as impact to the tank itself - I believe it to be completely safe for use from outside an aquarium.
• I've found it to be more effective if all water movement in the tank is stopped during laser sessions. The minimizes cooling keeps the targets still.
• I've ordered a second pair of safety glasses (~$50) to enable an observer to photograph and video the process. Without eye protection, I would not allow anyone (or any pet) anywhere near the room with an active laser.

Early Results

Wow"¦ there is no doubt in my mind that this is an effective method to kill virtually ANYTHING in an aquarium. The immediate results vary based on the type of target. So far I've tried the following,

• Aiptasia "“ Highly effective. Within seconds, you can clearly hear a "œsizzling" sound as they literally begin to boil "“ often following by a "œpop" as they explode. They try and retreat as soon as the laser hits them. Assuming you have a clear shot at the hole "“ this only increased the lasers effectiveness as you're able to focus all the energy in a single spot (as opposed to lasing the fully opened Aiptasia. I will be very surprised if any of the Aiptasia targeted return. Time to total kill - <10 seconds.
• Green Star Polyps "“ Highly effective. Within in seconds they are toast. They burn very quickly.
• Xenia "“ Effective. Killing Xenia does to take longer than the Aiptasia "“ I'd estimate about 30 seconds. This may be due to their lighter color. It seems best to focus on the base of the polyp often resulting in a popping noise. Time will tell if they return.
• Mojano "“ I dont' have any Mojano in any of my tanks, but I see no reason why the results would be much different. It may take slightly longer to kill larger specimens, but the end result should be the same"¦death by LASER.
• Valonia "“ Too soon to tell. The laser quickly cuts directly though both walls of any Valonia bubble but more time will be needed to see if this actually kills the bubble.
• Miscellaneous Algaes "“ Too soon to tell. When lasered, virtually everything living begins to pop and smoke. It's amazing how clearly you can hear the sizzling sound. It would take a lot of time to destroy large patches of algae, but I believe it is possible.
• Cyano "“ Highly Effective. A quick pass makes Cyano disappear. It works although I think there are more effective means to combat Cyano.

I'll follow up with before/after photos and video once I receive a second pair of safety glasses for an observer to film and with updates as to if any of the targeted pests regrew.

 

[CJO]

• Valonia "“ Too soon to tell. The laser quickly cuts directly though both walls of any Valonia bubble but more time will be needed to see if this actually kills the bubble.

I wonder if it would be better to defocus the beam a little for the valonia. This way it would likely heat it up enough to kill it before cutting through the skin.

CJ

 

[CalmSeasQuest]

I wonder if it would be better to defocus the beam a little for the valonia. This way it would likely heat it up enough to kill it before cutting through the skin.

CJ

I'm not sure - The challenge is as you defocus the endpoint, the power falls off dramatically. With the cooling impact of the water, It's tough to know just how miuch energy is being imparted to the Valonia.

I tried a couple of different methods, lasering the entire exterior of the bubble (you can see the pigmentation being "erased" as you lase the surface. And carving a large hole in the bubble.

Time will tell if either are effective means of control.

 

[Sk8r]

I'm willing to 'let Mikey try it' until I know if there are issues with the tank glass heating, or heating a rock by accident and blowing through the bottom of your tank... inquiring minds want to know.

 

[CreatiVe2]

Calm Sea - Great writeup! I also saw your thread on laserpointerforums

We have other Laser enthusiasts in this thread
and my personal video below - This is only with a 700mw 445nm Laser - ive had this for over a year, and never thought of taking out pests, until i saw the thread above!

<iframe width="853" height="480" src="http://www.youtube.com/embed/Cbk7mA5PuAQ" frameborder="0" allowfullscreen></iframe>

 

[jrpark22000]

Adding the link to the laser forum topic.

http://www.reefcentral.com/forums/showpost.php?p=19565561&postcount=244

There is some good info for high power laser noobs like myself.

 

[CJO]

I'm willing to 'let Mikey try it' until I know if there are issues with the tank glass heating, or heating a rock by accident and blowing through the bottom of your tank... inquiring minds want to know.

Heating the glass should be a non-issue unless you don't clean your glass. Also, heating a rock hot enough to break the tank glass would be hard to do with all of that water in there to cool things off, though it might be possible if you heat a portion of it right next to the glass.

CJ

 

[CalmSeasQuest]

I'm willing to 'let Mikey try it' until I know if there are issues with the tank glass heating, or heating a rock by accident and blowing through the bottom of your tank... inquiring minds want to know.

I've used an 1800mW (the largest output I've seen tested in marine aquaria this far) on both glass tanks (both flat glass and a slight bow front) and an acrylic tank. I don't have a IR thermometer, but I was unable to detect any temperature change. I don't beleive that heat transfer will be a problem.

Even with prolonged exposure, I don't think we have to worry about any rocks exploding. A few thoughts,

• As I understand it, a laser focuses light energy up to 100,000 times, thus the 1800mW laser being utilized is the equivalent of up to ~180,000 watts of energy being delivered to the pin-point focus point. The energy is so focused, you can completely "vaporize" an Aiptasia polyp nestled in the middle of a desirable colony with little or no damage to corals in the immediate area (assuming your hand is steady enough.) All that said, we're still dealing with only 1.8 watts of energy.
  
• Add to that pin-point focus, the fact that we are lasing items under water. The cooling effect is pronounced. You can easily tell a difference in still water vs moving water. Lasing is much more effective with pumps turned off.
  
• Lastly, the lenses used to focus the laser itself is glass.

I'm not concerned at all about damage to the aquarium - I'm more concerned with the risk of damage to the operator, nearby observers or the livestock itself as aquarists rush to Lasers to rid their tanks of pests without proper training or equipment. While I beleive the use of Lasers in marine aquaria will provide significant benefit, I also think the risks are being underestimated.

i.e. Much is made of someone being subject to Palytoxin, from which a full recover is "usually"expected. Using high power lasers around glass and acrylic cubes full of potential reflection angles carries with it a high likelihood of eye damage (potentially permanent) to either the user or observers not properly protected - Especially since the laser operator (assuming he/she is using the appropriate safety goggles) by design, won't be able to see many of the reflections. Add to this the fact that the safety goggles are nearly $50, and I can see instances where observers are watching Aiptasia being "fried" without protection...very scary.

The tank inhabitants are subject to even greater risk, as they will not have the benefit of eye protection. I've also noticed the "sizzling" sound seems to attract fish, perhaps out of pure curiosity.

I'm excited about the use of lasers in our tanks, but watching it slice through cardboard almost instantaneously has me treating it with the utmost respect.

 

[jrpark22000]

Heating the glass should be a non-issue unless you don't clean your glass. Also, heating a rock hot enough to break the tank glass would be hard to do with all of that water in there to cool things off, though it might be possible if you heat a portion of it right next to the glass.

CJ

Adding a thought, if you were to inadvertently or otherwise point the laser at a pane of glass who is painted black it may be sufficient to cause a problem. Assuming the laser had a tight focus for long enough duration. Not too likely, but a possibility.

 

[jrpark22000]

I've used an 1800mW (the largest output I've seen tested in marine aquaria this far) on both glass tanks (both flat glass and a slight bow front) and an acrylic tank. I don't have a IR thermometer, but I was unable to detect any temperature change. I don't beleive that heat transfer will be a problem.

I do and I did test. The IR thermometer read no change in temperature through ½ starphire glass.

I'm excited about the use of lasers in our tanks, but watching it slice through cardboard almost instantaneously has me treating it with the utmost respect.

:deadhorse: A small part of the reflected beam burnt my exposed wrist. I have no idea where the reflection was the rest of the time I was using the laser. While wearing the glasses you cannot see any part of the laser beam other than the focal point. Just as with a firearm, one mistake could permanently affect yours or another's life.

 

[Randy Holmes-Farley]

A reflected beam burned your skin? Imagine what it would do to your eye?

IMO, this sounds so dangerous to ones eyes that I think this thread should be flagged with a huge warning if not removed. I've never seen a thread advocating something so dangerous before (and I've seen a lot of dangerous practices in threads. )

 

[astvinr]

So you are technically using a weapon to kill pest animals in your aquarium.
This seem stupid to me.
I'd leave the lasers for the professionals.

Pests can be avoided by quarantine. And removal can be done numerous ways, chemicals, biological, physical..

And you wanna use a WEAPON for this instead, risking your pets and your own safety for what. Reliving the passed while burning ants with a magnifing glass? Please tell me im wrong.

Because this is very disturbing.

 

[gillies]

Boiling water in an eye wash syringe serves the same purpose, but you do have to get your hand wet.

 

[Sk8r]

I'm tending to agree---with the vision of the fact you can order anything off the internet, and arming random novice reefkeepers with something that can permanently blind or burn the user or some bystanding kid who stands at a lower level, with, say, a bounce off the reflector or other shiny surface, as someone not remotely used to handling a weapon-sort-of-thing swings it off-target with the button pushed---that's scary, guys.

 

[jrpark22000]

A reflected beam burned your skin? Imagine what it would do to your eye?

You will be blind. It is paramount everyone heads extreme caution with high power lasers.

So you are technically using a weapon to kill pest animals in your aquarium.

Technically, almost anything can be a weapon. Please let's not turn this into a discussion on weapons.

Yes, a strong laser is dangerous. Does this mean it should be banned or deleted? This thread and the other have warnings. Does removing this thread stop the people who don't know better from doing something dangerous or does leaving a informational yet warning thread alive serve a better purpose?

Pests can be avoided by quarantine. And removal can be done numerous ways, chemicals, biological, physical.

Yes, and this is just another way. Not every solution is suitable for every case or person.

 

[jrpark22000]

I'm tending to agree------that's scary, guys.

This is another warning for the device mentioned above.

http://unitednuclear.com/Insert_For_Class_4_Handheld_Lasers.pdf

And further information abour blue lasers.

http://en.wikipedia.org/wiki/Blue-light_hazard

 

[Sk8r]

This is a quote from the laser forum cited:

"I imagine that if you do this very many times your aquarium fish will go almost blind. Perhaps in an aquarium being blind wouldn't be such a disadvantage.. but if they were my pets I would get a piece of dark plastic to put into the water so the fish couldn't see the laser.

Reflections off the glass can also cause eye damage to anyone (sk8r adds: or pet) in the room at that power, so either do this when no one will accidentally walk into the room or have safety glasses for everyone in the house."

 

[CreatiVe2]

jrpark - thx for doing the right thing.

I posted that vid just as a demo, now its on 10+ reef forums getting some 'bad credit'.
but in reality, isn't that why we are here? To educate ourselves before making a larger $$$ purchase? especially because it is dangerous.
I am pretty sure we have mastered research already being in the sw hobby.
before getting a laser you will HAVE to see warnings everywhere, its part of that 'hobby'.

However, if you were one of those people "breading aiptasia" bc it was "pretty", then yes, please try joes juice first, and close this thread.

Ignorance doesn't need to be blasted with negative feedback, it needs users like us to inform everyone what they are capable of. Good and bad. If this isn't for you there's no need to 'scare' people that are just trying to educate them self.

sk8 has a good point though. I can shut the door to my aquarium room, and remove all pets/people. If you have an open area aquarium, you will have to wait to make sure nothing is around

 

[CalmSeasQuest]

A reflected beam burned your skin? Imagine what it would do to your eye?

IMO, this sounds so dangerous to ones eyes that I think this thread should be flagged with a huge warning if not removed. I've never seen a thread advocating something so dangerous before (and I've seen a lot of dangerous practices in threads. )

A primary goal of this thread was to inform and educate prospective users of laser technology as to not only the benefits, but the significant safety concerns and safeguards that need to be adhered to. As the cost of high power diodes drop, it is a fore drawn conclusion that people will experiment with lasers in marine aquaria.

Rather than ban, I hope RC recognizes the opportunity to educate with the goal of avoiding injuries. In this case, the education is paramount, not only to protect the user, but any observers (intended or inadvertent.)

To stress the importance of education, consider someone who purchases or borrows a laser to kill aquarium pests. They will likely not know that the very safety goggles designed to protect him/her from injury, prevent the viewing of beam reflections potentially dangerous to both livestock as well as any bystanders.

As for educating fellow aquarists - If not us, who?