[ocker]

Hi all,

Long time ago I did amateur chemistry, still have all the equipment but not active anymore.
But now I am trying to remove phosphate from my well water (because I want to use it for my pond)

The well water contains 4ppm of phosphate (detect with easy pond test kit)
That is way to much and will result in an algae bloom.

I found that using electrolysis of aluminium anode and cathode will remove the phosphate.
It should generate almost insoluble aluminium hydroxide I believe.
After 24 hours of electrolysis with 5v in a 1000 liter tank there is no phosphate detectable anymore.

But I would like to test how much of soluble aluminium compounds are left in the water,
They can be toxic for aquatic life is what I understand.

Can anybody point me in a direction on how to test for aluminium?
(I can not find normal priced commercial test kits)

Hope this is a question I can ask on this forum.

Kind regards

[Corribus]

The gold standard would be ICP-OES or ICP-MS but that is beyond the means of an amateur in terms of price and expertise.

A better option is an official NEMI method for aluminum analysis - the eriochrome cyanine test. You would need the chemicals as well as a UV-Visible spectrophotometer capable of measuring light intensities at 535 nm. UV-Vis instruments capable of doing this test can be found relatively inexpensively and this test would be doable by an amateur.

https://www.nemi.gov/methods/method_summary/7398/

There are also a number of available colorimetric test kits which would give you a semiquantitative analysis. I'm not sure what you interpret as "normal price". Millipore Sigma sells a colorimetric test for Al, with a price of about $1-2 a test. (Ofc you would want to buy the strips appropriate to your concentration range of interest.) You can find these test kits at other vendors as well so I'd shop around.

https://www.sigmaaldrich.com/US/en/product/mm/114413
https://www.sigmaaldrich.com/US/en/product/mm/114413