Does Anyone Know If Aluminium Will Affect Fish

[Spishkey]

i have here two very large 'tubs' made from aluminium, now ive been using them as a raised veggie garden but now i have a proper garden at the new house i no longer need to use them. my fella has came up with the idea of using them as the structure for the indoor ponds.....do you think the turtles or fish will have any reaction to it? would it be safer maybe to line it with pond liner first?

 

[star4]

Hi, I would use a liner to be safe. Although aluminium does not "rust" it will corrode. I have copied the following for you.

Environmental effects of aluminum
The effects of aluminum have drawn our attention, mainly due to the acidifying problems. Aluminum may accumulate in plants and cause health problems for animals that consume these plants.

The concentrations of aluminum appear to be highest in acidified lakes. In these lakes the number of fish and amphibians is declining due to reactions of aluminum ions with proteins in the gills of fish and the embryo's of frogs.
High aluminum concentrations do not only cause effects upon fish, but also upon birds and other animals that consume contaminated fish and insects and upon animals that breathe in aluminum through air. The consequences for birds that consume contaminated fish are eggshell thinning and chicks with low birth-weights. The consequences for animals that breathe in aluminum through air may be lung problems, weight loss and a decline in activity.

Another negative environmental effect of aluminum is that its ions can react with phosphates, which causes phosphates to be less available to water organisms.


It would probably take years to corrode, but if you have had plants in it may have already started.

Hope this helps

 

[saltynay]

star4 you are referring to aluminium ores whilst these bins would be covered in a coating of alumina not pure aluminium. Alumina is an already oxidised sample of aluminium and its ions are fairly non reactive, incidentally depending on the impurities it creates rubies. It will remove flourine compounds out of the water which I believe are needed or might hinder plant growth (cant remember which way round) however eventually it will become completely reacted and inert. If fluorine is needed for plant growth like I think it is as at my LFS they do sell bottles of it so you could add it back in.

I would age the tubs by filling with water leaving for a couple of hours then removing and repeat.... do this for a week or two should make the alumina inert, water your new garden with the excess . You could line it if you wish would save the hassle of ageing them but I don't think it would give a nice visual effect.

 

[Spishkey]

the planters are made from solid/pure aluminium sheets, bent and moulded into shape...dont know if this makes any difference? (fella made them at work, he's a constructor and uses them normally to make silos with )

 

[saltynay]

High quality Aluminium is rapidly oxidised when it comes in contact with air unless protected by something. It creates a layer of alumina which is Al2O3 and a generally white crystalline solid on the surface of the aluminium. If memory serves and it should as I have an advanced level exam on this and other chemistry on Thursday, it should be safe for fish provided the majority alumina has previously reacted with the fluorine present in the water.

 

[Spishkey]

well they've been outside for over a year through wind rain snow frost and hot hot sun, and show no signs of corrosion. will give it a try with some feeder fish first or so i have two so will line one and leave the other, see what happens many thank saltnay and star for the advice

 

[saltynay]

Alumina is very hard to corrode and protects the pure aluminium it coats extremely well. The issue will be if the alumina has reacted with sufficient dissolved fluorine in the water to be no longer reactive. Using feeder fish and using them as a test is the best course of action by far.