Safe metals in freshwater tanks.

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dyrodium

Aquarium Advice Apprentice
Joined
Nov 10, 2005
Messages
16
Location
Sydney, Australia
Before i start im sorry if this has already been brought up, i tried a search and didnt find anything!

Now...
In making up my new 3 foot tank setup i'm aiming for something unusual and striking, a kinda merge between my fish keeping interest and my construction interest, so i've drawn up a few designs, but one thing which would be very cool to incorperate would be some metal (like thick sheet cut into funky shapes). Only problem is im well aware of most of the properties of most metals... they really dont like water (especialy salt water but this is fresh... salt causes chaos on almost all metals save titanium 8O )
Does anyone know what metal would be best to use, if any? Im not sure about aluminium... and Ti is sorta out of my budget (though i do have some for other uses). Im thinking stainless steel maybe? :?
Thanks!
Angus
 
the only safe metals to my knowledge are, aluminium stainless steel and titanium. as you might know there are thousands of different alloy contents of aluminium and i am not sure if all are usable or if only a few alloy contents are. Titanium is by far the best and safest to use, stainless is safe - its even used in some algea scrapper's, and aluminium would be after we check out on the alloy content.

i am not exactly sure what sort of disigns you were wanting to make, however there is a cheap way to get titanium, it will cost you 2-3 USD a peice but go to your local bike shop and ask them for a titanium (Bike-wheel) spoke, it should only cost a few bucks, and you can bend that to a shape pretty easily. your probably wanting to get the metal in sheet form, but if you can use a spoke instead you might save a few bucks and have a safer aquarium.

hth

bry
 
JProx said:
the only safe metals to my knowledge are, aluminium stainless steel and titanium. as you might know there are thousands of different alloy contents of aluminium and i am not sure if all are usable or if only a few alloy contents are. Titanium is by far the best and safest to use, stainless is safe - its even used in some algea scrapper's, and aluminium would be after we check out on the alloy content.

going to agree with everything here. just posting really to second your comment about alluminum alloys, IIRC it was mostly in regards to alluminum alloys in SW. If this is a FW system, Stainless will likely be your best option both for it's working properties (compared to alluminum) and its resistance to corrosion in a FW system.

welcome to AquariumAdvice.com! looking forward to seeing plans! :wink:
 
You can add gold 14k or higher to that list as long as there is no electric current, but at that point you have other far worse problems. 8O

But for the most part, if the metal will rust or tarish, you should keep it out of your fish tank. This is why most everything in your fish tank is plastic or plastic coated...
 
lol yeah you don't really want a current through your tank! 8O
Thanks for all the advice, i've decided on stainless as it seems most suitable. The basic idea is a large about half inch thick strip of stainless bent or hammered into a half mobius strip sort of design, and another piece cut into a shape simmiler to the end of a spanner supporting that, other things are falling into place in my ideas too. The main concern is that there is no sharp edges that the fish can hurt themselves on, so thats why ill use thickish material and grind the edges down so its blunt. Still also working out the fish involved, but may be some halfbeaks, scats or monos (bred for fresh water) or something else black and silvery, maybe even mollies, lol the price is right for them anyway! :)
 
the only safe metals to my knowledge are, aluminium stainless steel and titanium.

NO METALS ARE SAFE.
I can't believe anyone actually said it was.
Every metal corrodes in a matter of time, oxides form on the surface and will poison your fish and entire aquarium. It's just a matter of how long it takes.

Note: Oxygen also sets off corrosion, add a minute electrical current from a powerhead or whatever and watch the oxides form.

Stainless steel is the worst, it takes longer to corrode but the effect is five times worse then any others, it lodges into your system and does not dissolve, it just keeps rotting.

Mild steel is better it DOES dissolve through the system eventually but still causes serious harm.

Aluminium is more dangerous in the fumes it emmits from the corrosion. It will be like running a diy c02 with the poisonous gases into your system.

I am a qualified metal engineer, corrosion is a part of the process.
I shudder everytime someone says they screwed a piece of driftwood down with stainless screws. IT WILL KILL YOUR FISH AND POLLUTE YOUR WATER.
Do not say you weren't warned.

Matt.
 
Ah... i suspected as much... :x
So if stainless is dangerous, would coating it in something make it less so? I mean... if something did get through it would be pretty obvious and a half yearly or yearly re-coat to keep waterproofness would be needed.
Would that be effective? If not i'll have to scrap the whole idea... :cry:
lol or mod it insanly :)
 
DeFeKt, i'm willing to bow out to your experience, but I have a couple questions. There are a number of standard pieces of equipment of almost any aquarium that has at least a small amount of metal, usually stainless steel. Such as filter impellars, power head impellars, the titanium heaters especially. Is it that these are usually such small pieces that we don't see them causing detriment?
 
Hmm thats a good point, perhaps its the fact its only a small amount compared to the massive chunks i wanted to use... does anyone know if pvc plumber piping is ok?
 
pvc piping is A-ok, without a doubt, even the chemicals to clean and seal the joints are safe.

sorry about the metal suggestions though, you see metal in tanks on occasion from algea scrappers made by major manufactors (like kent marine) and even titanium probes in high end salt water sensory kits. no idea why those metals don't cause problems, i have had several power heads in use on my reef tanks for 5yr+ yrs and never had them corrode. anyway i am still astonished by DeFeKt's disputatious comments though.
 
If metals are so dangerous, then in the wild, why do fish make homes out of them, like soda cans, etc, and live a natural life?
 
Wolf - your forgetting about water volume, a lake will have several thousand (maybe even 100-thousand) gallons, and that one 1 pop can won't do much to the whole system. Pearl harbor is loaded full of ships with corals growing on and around them, that’s because the ocean is billions of gallons large, and its sweeping in new tides all the time, and pushing the 'toxic' water to less inhabited areas, or maybe an algae farm that will actually 'use' the metals. In our tanks we have 20-200 gallons, and maybe 20% of the total volume gets changed out once a month. Metal will have a much more drastic effect on the aquarium system, than the wild ecosystem because of how much water (or less water) they have.

And if any veterans are browsing the forum today, I just wanted to personally thank you for your service.
 
Just use whatever metal you want and coat it in clear plastic. thats only if you want a REAL metal look.
Just an idea. lol
 
a good coating of aquarium safe sealert I imagine would be fine untill it wears off.

It's not the metals that are toxic, it's the oxides (rust) that form on them.
A pump running 24/7 with moving metal componants in it does not sit still long enough for it to start corroding.
You'll also find that they do not have "bare" steel screws or anything, they are 99% of the time powder coated or anodised. If not, it's a cheap pump. They are also covered in a lubricant/soft sealer, like vaseline to prevent seeping into certain areas which would do the same thing.
As for zinc, I don't know the content of it or the percentages, i've never worked with it. however, Austal Ships where i did my apprenticeship puts a zinc anode on the bottom of their boat hulls every few metres, what happens is they run an electrical current to it and start corrosion in the blocks. It attracts the elements that start the process and the blocks of zinc are eaten away before the aluminium hull starts to corrode. So instead of pulling a 100metre boat out of the water once a year to revamp the aluminium under the water line, you just send a diver down to replace the anodes. I can imagine then that this would be more lethal then the others due to it's quick decaying capability.
Also keep in mind, this won't happen straight away, but it will happen.

HTH

Matt.
 
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