Backyard Aquaponics
A place to discuss aquaponics

Certain metals and alloy are a bad idea in AP:

-Zinc
-Copper
-Brass
-Bronze

Any others?

What ones are ok?

Iron (yes it will rust but it won't poison the system)
Mild Steel (yes it will rust but won't be a poison)
Stainless Steel

What about:

Aluminium?

Others?

Titanium is pretty safe. Water heater elements made of Incoloy are not safe.

I think death metal is bad for AP fish, I find it pretty distressing myself

Sodium and Potassium are metals that are good for fish, but it's not a good idea to drop chunks of either into the FT!

Any thoughts on aluminium?

I have read oxides and salts of aluminum to be neurotoxic. I avoid aluminum in cookware. Is fantastic to machine though!

Gunagulla- I find Death Metal to be an acquired taste. Power Metal! Now that gets the fish and plants growing!!!

There was a scare a while ago that aluminium caused Alzheimers among other neuro degenerative diseases from research conducted in Japan. It turned out thought that the stain they were using to prepare their slides of nervous tissue contained an aluminium oxide.

Modern greenhouses use a lot of aluminium like a lot, massive amounts for all the glazing bars, gutters and the like. It would be good to know whether having water dripping from these parts into a system was, could be a problem or not.

Yea, it's toxic, especially in acidic water, plenty of info online about Aluminium toxicity in fish

So aluminium submerged in system water=bad
What about above and around a system?

Alway's thought that aluminium reacted badly with high ph could be wrong though.

Edit

I would have thought not Stuart, aluminium oxidises and that forms a protective coating, if it was water soluble my old Landy would have dropped to bits years ago.

I used aluminium flat bar to brace my DWC rafts. They were not directly in contact with the water but they were constantly damp/dripping.

You might be right. Acid/Alkaline could be both bad.


So does zinc and copper but we know they are bad.

That's debatable but the conditions you mentioned were dripping from condensation not from acid rain (and I am assuming the condensed water would be ph neutral).

Anyway http://www.seachem.com/support/Aluminum ... xicity.pdf

yea not a good example sleepe, I wouldnt purposly submerge some in the FT is probably what I should have said anyways.

Neither would I, but if I had an aluminium framed greenhouse (I wish) I wouldn't give a rats ass about condensate dripping in the FT.

As mentioned, a layer of Al2O3 forms on Aluminium in air, and this is insoluble. However, Ammonia will corrode it, but you are not likely to have much free Ammonia around.
I'd be inclined not to have water drip from Al into my system, especially for a long term installed system.