Question:

I have recently bought a new tub of the ocean salt.

When mixed it is leaving a brown residuue on the bottom of the buckets.

I belong to a marine club and no of many other members who are experiancing the same problem.

Can you comfirm if the salt is contaminated of this is a harmfull substance.

Answer:

This brown residue is detailed on the instructions in the tub and is a residue of ferric oxide/hydroxide from the manufacturing process, (like Rowaphos). This product will bind to any phosphates and heavy metals in the water and allow them to precipitate out for removal via the skimmer.

The presence of the ferric deposits depends on the calcium source that we use to boost the calcium level. The best calcium source to use for incorporation and solubility into the final salt solution is the one which contains this ferric residue however as people tend not to like the brown deposits we do not generally use it. We have however had one batch in the UK, of which you must have received a drum, which did have such a residue as there was a supply issue on the normal calcium chemical.

This deposit is not harmful in any way and is actually beneficial to the final mix.

I hope this answers your query