Time. The surveyor said it's best not to drink from them. Any Ideas on what can be done so they are safe to drink from.

Use them as fuel tanks but definitely not as water tanks.

Can you please elucidate and inform the group as to what has actually happened to your tank that caused the surveyor to say not to drink from them?

Aluminium is a very reactive metal and as such very quickly forms an inert oxide coating, so unless something else is tainting the metal and causing some toxic compound to form in the water I would just as likely say that it is equally unsafe to drink from a new aluminium tank.

As for the diseases that have been linked to aluminium in Charriot's post I can't comment on Anemia or Bone disease but Alzheimer's has now been pretty well ruled out as being caused by aluminium and by association I am including Confusion and difficulty concentrating with Alzheimer's as that is a prime sympton of Alzheimer's.

I include this link from the UK www.alzheimers.org.uk/about-dementia/risk-factors-and-prevention/metals-and-dementia?documentID=99 as I give more credence to the UK than I would generally to the US, which by and large still allows the pedaling of snake oil remedies.

Bladders are a cheap alternative , another good tip is to not fill your drinking water tanks from a garden hose it leaves a terrible taste. Garden hoses are made from rubbish you can buy proper food grade hoses for this or fill up plastic jerry's direct from the tap and pour them in.

go the bladders, but get an inline 2 stage filter from reece or the like. one filter at 5 micron, the 2nd stage at .5 micron. itll be perfectly tasteless. cost about the 250 dollar mark.