Thoughts On Metal Work In Water?

[coolie]

What are your thoughts on metal work in water? Years ago, I used to think it would be like putting dissolvable rock in there.
 
But recently I've added more things like steel metal hooks under water etc, and don't seem to have any problems?

 

[Stimo]

as long as it's stainless steel and doesn't rust?

 

[coolie]

Yes, stainless steal, but stainless steel does eventually rust, just a lot slower depending on the quality, and although I'm freshwater, I'm sure marine might speed the whole process of oxidisation up?

Personally I think it's ok, but I just wondered what other people thought.

 

[TwoTankAmin]

Oddly enough what damages stainless steel is salt and chlorine. SS in sw does much better when is is exposed to oxygen. Corrosion tend to happen where flow is absent such as place where things connect and the connections minimize flow at contact points. In fw the biggest culprit is chlorine or bromine as is used in swimming pools. The suggestion for preventing damage to stainless in chlorinated environments is to rinse things regularly in clean water (i.e. no chlorine or bromine).
 

 
Stainless steel resists rust and will stain “less” than other types of steel. What may appear to be rust is actually surface corrosion. When stainless steel comes in contact with chloride (which is found in seawater) or chlorine (which is used in swimming pools), the protective chromium oxide layer gets penetrated and allows corrosive attack to occur. Thoroughly rinsing all your equipment with fresh water after use in salt water or chlorinated water is the best way to prevent corrosion.

from http/www.halcyon.net/faq/ss_care
 
Since the amount of chlorine one adds to a pool is more than you would find in your tap and way way more than might ever be in a tank, I think stainless in a fw tank would likely outlast the tank and/or the fish keeper.
 
That said, I do use SS screws with drifwood when it need a slab on the bottom to hold in in place in the substrate. However, I will also use a plain old staple to attach plants to wood. I do not thing a rusting staple or two in 20 or more gallons of water that gets changed weekly will be an issue and so far it hasn't been as far as I can tell.

 

[Tongue_Flicker]

Brass alloy netting cages are used in some commercial-scale fisheries. Some faucets and underwater valves are also made from bass alloy. It is corrosion-resistant given that water quality retains very minimal ammonia levels and is said to have antimicrobial properties

So is zinc in coins, given that your pH level does not go any lower than 7.5

 

[coolie]

Thankyou for your points twotankadmin. Tongue, that wouldn't be very re-assuring on zinc considering neutral is at PH 7.

Maybe my assumptions that stainless steel will always rust eventually, is based on what happens to the chrome work on my motorbike and other anecdotal evidence, rather than any solid science.

 

[Tongue_Flicker]

Well yeah. I would've said pH7 but that would be too risky. Not that anyone would attempt to put a zinc coin in a fish but you'll never know especially if you have kids at the house Lower than 6.9 will already start very little reaction

 

[M4R13Y]

Am I correct in thinking that copper and anything that contains copper is a no no in aquariums ?


Thanks M4

 

[coolie]

Yes, that's correct. Some organisms are more tolerant than others. Invertebrates, and your snails and shrimps and so on are known to be extremely sensitive to even minute amounts in parts per million.

 

[coolie]

So, does anyone know, does zinc actually "dissolve in acidic water", or does it simply oxidise?

 

[coolie]

See, it seems to me that on paper, Zinc reacts with water to form Zinc Oxide or Zinc Hydroxide, However old cold water tanks were galvanised iron. What I think happens in practice is, the Zinc oxidises slightly on the outermost layer, and this protects the rest of the zinc underneath. So... I imagine your Zinc coin is not dissolving in acid PH.