Zapping Mojanos

[Paul B]

I have posted ways to eliminate mojanos before but this high tech way is the baes, and most fun.
I use 24 volts DC which can't hurt you and I inject it into a mojano with this home made electrode. It uses stainless steel sewing needles in an acrylic tube sealed with a glue gun.

I thought it was the electricity doing the job but now I am now fairly sure it is the gas generated from one of the electrodes that destroys the mojano and not the current.
Here is a close up of the electrode emitting the gas. (I am not sure if it is oxygen, hydrogen or chlorine)
The anemone turns white and totally disentigrates and becomes part of the bubbles.

 

[Cibo]

how does it make the gas? if it just dc

 

[Paul B]

Electricity splits water into hydrogen and oxygen. I believe it is the oxygen oxidizing the amemone.

 

[Keith P]

Paul, a DIY is in need :sgrin:

What kind of power supply are you using? Any idea of what the current draw is?

 

[Paul B]

I am using a home made low voltage DC power supply which is the big black thing on the left of the picture but it is way overkill. The current is 350 miliamps which is about enough to light a flashlight lamp.
I am working on a smaller, self contained battery powered model.
I am sure a small DC power supply such as what powers lap top computers would work fine, just keep your lap top out of the water.

This picture is how I connected the stainless steel needles to the wires, I used shrink tubing on the connections.

 

[SevTT]

I thought it was the electricity doing the job but now I am now fairly sure it is the gas generated from one of the electrodes that destroys the mojano and not the current.
Here is a close up of the electrode emitting the gas. (I am not sure if it is oxygen, hydrogen or chlorine)

Nice!

The gasses generated are different depending on which terminal they're being generated on. The one that's putting off a lot of bubbles is generating hydrogen and probably binding metal ions to it -- sodium, calcium, iron, etc. The other is generating oxygen, chlorine, and probably a few other gasses.

For electrodes, your best bet would be graphite. Steel often contains nickel, chromium, and copper, and none of these are good for your reef tank -- and all of them definitely are being released when you use this tool, if they're in the metal in the first place. Of course, it's a tiny amount, but I'm paranoid. %)

 

[Paul B]

Thanks SevTT. I am not that paranoid and use stainless steel in many places in the system and have always used it. I don't think anything released out of 3/16" of a stainless steel needle in 100 gallons would hurt anything.
I have thought about graphite but it is brittle at the size needed so I will stick with the stainless. The device is only active for a few seconds that it is stuck in the mojano.
I did do an experiment and used a pint of salt water. I ran the thing in there for a minute and then hatched brine shrimp in that water. I know that is not a great test but it did prove to me that anything that is released is not real toxic.
It did turn the pint of water slightly yellow though.
Actually, I think I got a better hatch of shrimp in that water than new water, but that is another experiment. :biggrin:

 

[wallysworld]

This is a cool idea! This is some what similar to what they use in the pool industry. When they say saltwater pool they really mean saltwater until the electrode device converts the salt to chlorine.

Have you tried using a battery? If so how long did it last? Also what kind of switch are you using? I would think a momentary switch wouldn't generate too much extra gas?

Again this is a great idea. I am going to build one and test (since my file fish is lazy!).

Btw, using surgical stainless should be fine. I would not use just any stainless.

Thanks!

 

[Paul B]

The electrode is emitting chlorine, big time. I found a cheap way to make Clorox.
I tried it for a minute in a small volume of water and smelled it, it almost burned my nose off. This is the substance that is oxidizing the mojanos.
I replaced one of the stainless stel electrides with carbon because the stainless steel on the side that does not produce the gas corrodes very fast. The carbon seems to last forever.

 

[Paul B]

Well the thing seems to be perfected. I had to replace the carbon because it had copper in it so I used graphite from a carpenters pencil for the terminal that corrodes quickly. The chlorine emmitting electrode is still stainless steel but it is thinner now. The entire thing is small and compact with a push buton momentary contact. There is a light in it to tell you it is working. Of course the light don't work so it is back to Radio Shack for a different light but that is very easy to replace. I just don't know how long it will work.
The transformer is 18 volts which is rectified to give out DC.
I used a stainless steel spring to connect the graphite to a wire, it coils tightly around the graphite to give a good connection. The spring and wire are encased in clear
"Goop" glue. I use Goop on another thing that I patented for the hobby that stays underwater so I know that will be no problem.
After I do a few more tests, and if they are successful, I will mail it to someone to test.

 

[NL146]

...I use Goop on another thing that I patented for the hobby...

Interesting! Out of curiousity, what was that other thing?

 

[Keith P]

I'd love a proto-type! I may try to build one myself.

"Goop" as in Goop brand glue?

 

[Paul B]

Interesting! Out of curiousity, what was that other thing?

http://www.breedersregistry.org/Articles/v4_i3_paul_b/paul_b.htm

Yes keith Goop Glue, you can use it underwater and it is non toxic

 

[Paul B]

 

[Paul B]

 

[Paul B]

A friend of mine owns a LFS near my home and his tanks are loaded with mojanos. Very large ones, so I am going to try to go there today and test the device on larger mojanos. I may need to bring a larger transformer to generate more power for these suckers
but it will be a good test.

 

[Keith P]

I'm going to try this. I have a 12V booster pack (for jump starting cars). I think I'll need a big resistor to bring the current down on the probes.

 

[Paul B]

You can put it in series with an auto lamp

 

[Paul B]

A friend of mine owns a large LFS and his reefs are loaded with mojanos so I made the mistake of telling him that I built this mojano zapper. He had to try it so I brought it there today and he loves the thing. He destroyed about 75 mojanos in about 15 minutes. And in his tank they are huge. There is no chance of them returning because there is nothing left of them.
I had a hard time getting the thing back from him but he gave me a nice rock with yellow polyps on it so I told him I would build a larger one for his deeper tanks.
I built a different model and after it is completed I will try it again on his tanks.
This is in the store's tank, those spots you see to the left are the bubbles along with burnt up pieces of mojano

 

[Keith P]

That is so cool. You may want to patent your design