Determine the concentration of limewater
...eased that irritates the corals. In this article I will give some details of aluminum in natural seawater, and will discuss the sparse literature on the toxicity of aluminum ions to marine organisms. I will also show that aluminum is indeed released from one of these types of materials (Phosguard, sold by Seachem). Finally, I will show whether added soluble aluminum irritates any of several corals in a test aquarium. Aluminum in the Ocean Individual soluble aluminum ions in the ocean largely take the form Al(OH)4-, but some are also present as Al(OH)3.1,2 Aluminum is also strongly attracted to organics and some inorganics (like silica), making the exact speciation of aluminum very complicated. There is also a fair amount of aluminum present in particulate and colloidal forms (typically in combination with silica), ranging in concentration from about the same as the soluble fraction, to much greater.3-6 Interestingly, aluminum is present at much higher total concentration in the Gulf of Mexico (~0.002 ppm for particulate forms only),4 the Atlantic Ocean (0.00014 – 0.0016 ppm))8-12 and the Mediterranean Sea (0.00008 – 0.02 ppm)3 than in the Pacific Ocean (0.0000016 – 0.00016 ppm)7,8 or near Antarctica (0.00008 ppm).9 This difference provides a significant clue to the origin of most aluminum in surface seawater: airborne dust l...