Size needed in the ocean?

[Cory]

I often see tanks destroyed by rusting magnets, metals and screws in the water. Im curious how big do you think that metal, magnet or screw would need to be in the ocean to have the same effect like in our tanks? Im guessing it would be like putting a screw in the ocean the size of hawaii or something right? What do you think?

 

[Ron Reefman]

To be honest, I've never seen a tank "destroyed' by a rusty screw or even a rusty magnet. I've had both and neither one caused any issues in my tank.

BTW, what is GFO? Granular Ferric Oxide... fancy rust.

 

[Cory]

Okay maybe destroyed is a strong word, perhaps tanks suffer episodes of rtn, or stn?

 

[Ron Reefman]

Okay maybe destroyed is a strong word, perhaps tanks suffer episodes of rtn, or stn?

IMHO, rust from a screw or a magnet does not cause rtn or stn.

 

[Cory]

IMHO, rust from a screw or a magnet does not cause rtn or stn.

Its not the iron its the other stuff, tin especially. Well i guess your in the penalty box for tbis thread lol

 

[Cory]

IMHO, rust from a screw or a magnet does not cause rtn or stn.

Im curious though, what made you determine that?

 

[Ron Reefman]

I had a big MaxiJet magnet used as part of a diy frag rack. It was in my refugium and when I discovered it was bad, it was split wide open and 10% to 20% of the magnet was gone due to rusting away. With all that in a 120g tank and a lot of sps corals, I never had any rtn or stn. So just my personal anecdotal evidence.

 

[NeonRabbit221B]

Likely you are both right. Magnets, especially neodymium made, can contain other materials.

Saying a rusted magnet can't cause an issue is as blind as saying that rust can destroy a tank by itself.

 

[Ron Reefman]

Likely you are both right. Magnets, especially neodymium made, can contain other materials.

Saying a rusted magnet can't cause an issue is as blind as saying that rust can destroy a tank by itself.

Excellent point!

 

[Cory]

I had a big MaxiJet magnet used as part of a diy frag rack. It was in my refugium and when I discovered it was bad, it was split wide open and 10% to 20% of the magnet was gone due to rusting away. With all that in a 120g tank and a lot of sps corals, I never had any rtn or stn. So just my personal anecdotal evidence.

Im guessing here, but id say that maxijet being inexpensive, doesnt use the more expensive neodymium magnets, but cheaper ferrite ones or whatever they are called, which wouldn't contain the real nasties and be mostly iron. No biggie.

 

[Randy Holmes-Farley Verified Community Expert]

Volume of the ocean is roughly 350 million trillion gallons.

That is the same volume as 3500 thousand trillion tanks with a volume of 100 gallons.

So you'd need 3500 thousand trillion screws.

If a typical screw weighs 10 grams, that is 35000 thousand trillion grams of screws in the ocean.

How big is that?

If each screw occupies a space of about 1 cm3, then that corresponds to 3500 thousand trillion mL = 3.5 thousand trillion liters.

One cubic kilometer is 10^12 (one trillion) liters, so that volume is about 3500 cubic kilometers.

Hope I didn't lose some decimal places. I'd hate for someone trying it to be off. lol

 

[RedFrog211]

I would like to point out that I am by no means a chemist or mathematician.

For fun, here is what I'm working with:

- Ocean's volume is 352 quintillion gallons (1.333e+21 liters)
- 22.4 Liters of water = 1 mole
- Sodium Chloride has a molar mass of 58.44grams/mole
- Salt water @ 1.025SG weighs approximately 8.6lbs (3900.9g)
- Seawater averages 35g of salt per Liter
- Sodium Chloride has a molar mass of 58.44 grams/mole
- At 25 ˚C ...

@Randy Holmes-Farley beat me to it.. lol

 

[Cory]

I love when i get wowed with numbers!

I cant visualize 3500 cubic kilometers lol

Is that like the size of the moon?

 

[Randy Holmes-Farley Verified Community Expert]

I love when i get wowed with numbers!

I cant visualize 3500 cubic kilometers lol

Is that like the size of the moon?

No, A cube 15.2 kilometers on a side gives about that volume.

 

[NeonRabbit221B]

@Randy Holmes-Farley pulls us back to the talking point to let us know we are literally arguing about nothing. lol

 

[Cory]

No, A cube 15.2 kilometers on a side gives about that volume.

Okay forgive my stupidity, but your saying a cube 15.2 killometers x 6 (since cubes have 6 faces) is the size it would be?

 

[Randy Holmes-Farley Verified Community Expert]

Okay forgive my stupidity, but your saying a cube 15.2 killometers x 6 (since cubes have 6 faces) is the size it would be?

No. A cube with a side the length of 15.2 kilometers. So 15 km x 15 km x 15 km

 

[Cory]

No. A cube with a side the length of 15.2 kilometers. So 15 km x 15 km x 15 km

Thanks Randy great thread! Girlfriends and grade 11....

That isnt actually very big when you consider the size of the ocean!

But im willing to bet the ocean would handle that differently than our tanks due to the abundance of life and amount of rock surfaces.

 

[Twitchy]

In reality the theoretical cube would need to be much larger, due to lack of exposed surface area

 

[stanleo]

Militaries around the world routinely sink old tanks, ships and vehicles in the ocean to create artificial reefs to combat the loss of reef habitats. I don't there would be a big enough piece of metal to disrupt ocean chemistry. All of the stuff we dump in there combined is probable twice the size of Hawaii.