Rust and Fish

[csababubbles]

I found a metal clamp on on of my return hoses that was submerged in my sump. It is very very rusted at this point. I will remove it and replace with a plastic piece soon. Did the submerged rusty metal clamp cause some issues with the water and fish that I should be concerned about? It must have been in the sump for months.

 

[jezzeaepi]

Run a polyfilter and see what color you get, then some carbon to be safe. Your probably fine.

 

[mnewby]

has any thing died in the tank insince it has been rusting if nothing has died and all are good i would not be to shook up then but i would get it out cause its not good in salt water

 

[leebca]

The best answer to your question is the good 'ol standby: It depends.

It first depends if the clamp was a steel or iron-based metal. It might even be a different kind of metal, but for the most part they are a kind of steel. "Steels" are a very large group of metals containing mostly iron. It is the other metals mixed in with the iron which have the potential to cause problems in a marine system. For instance, zinc and chromium are often part of the steel formula. These are heavy metal poisons to marine life forms.

Heavy metal poisoning comes usually as a chronic event, so it would not likely show itself right off. Assuming proper water changes, proper and diligent maintenance, the poisons probably reached an equilibrium in content. Some were removed (water changes, etc.) and replaced (continual dissolving of the metal).

Unfortunately, the chronic level of these kinds of poisons are not thoroughly studied on ornamental marine life forms. We know for instance that in very low quantities (ppb) that copper, zinc, lead, etc. are poisons to many invertebrates. But we don't know the long term effect of specific concentrations. Then, there are a lot of other metals to consider.

Also unfortunately, carbon and the absorbing resins can't remove these poisons in that low of quantity. For instance we know that when activated carbon is used to remove copper that the copper level falls below the level we can measure with the copper test kits available to the hobby, BUT the copper will remain at a level dangerous to marine life. So, both testing and using absorbents aren't the answer.

The additional factor is how those metals (if present) interacted with other chemicals and compounds in the marine system. Did the substrate absorb some only to slowly release it later? Did the live rock, decorations, filter media, etc. all or in part take up some of the poisons? Will those poisons come back out later and if so, under what circumstances? A pH shift? A salinity shift?

The best to hope for is that the original metal is one which is not contain 'large' quantities of these other metals.

As a minimum you want to perform a huge water change (90%). Sort of a
'low tide' to the system inhabitants. At the other extreme, is to tear down the tank, discarding substrate, rock, and all contents, including plumbing and equipment that comes into contact with the system water. Then, perform a cleaning of the components (e.g. display tank, sump, etc.) that will be used to start up the system again.

Regardless of the type of steel, perform the water change. My suggestion would be to find out what kind of metal that clamp was made of. Not knowing this or not knowing this for sure, then monitor inhabitants for any signs of disorder or dysfunction. In fish the symptoms will sometimes be nervous system malfunctions causing peculiar behavior and abnormal movement. In invertebrates, it might be as subtle as unwilling to extend polyps from protecting skeletons, etc. to death. If these signs show, then it is time to consider the extreme 'makeover.'

Lastly, review all your systems and replace metal clamps with plastic ones where you can.

 

[dnjan]

I have never heard of zinc being included in any steel alloy - zinc is usually applied to the surface (galvanizing) as a sacrificial coating.

Clamps, especially those that are showing rust in saltwater, are probably 304 or 308-series stainless steel. These alloys will contain on the order of 10% nickel and 20% chromium. The rest of the alloy will be practically all iron.

The preferred metal clamps for saltwater applications are made from type 316 stainless. They cost considerably more and are harder to find. Try West Marine.

 

[Herefishyfishy]

The preferred metal clamps for saltwater applications are made from type 316 stainless. They cost considerably more and are harder to find. Try West Marine.

Great info, Lee's too
Any luck with plastic clamps? As in any of them tighten strong enough to trust?

 

[leebca]

Depends on what the clamp is being used for. I have a nearby Ace Hardware. They have plastic C clamps that lock and then open with a lever. If it's a hose clamp, I use plastic.

You can find a lot of choices on the Internet.

 

[Ricko]

It probably isn't an issue dependiing on your volume of water as well. I had the same problem and when i went to fix it all bits of rust were falling off everything that i touched and no ill effects have come of it. As has been said though, some water changes and the corrosion can only last so long!!!