A quick squirt around showed me that the lucasoil product is probably ok to use , but will not protect any petseal lining. Petseal Ultra is stronger and should resisit the ethanol fuel. If any additive has a title like fuel system cleaner, water remover, oxygenator, octane enhanser and rust inhibitor, then the chances are that it will contain alcohol which will exacerbate the action of any ethanol fuel. If readers feel the need to enhance their fuel, then go for an additive that is comprised of a petroleum based additive, usually 95% I guess this is why this stuff is not to be used in diesel engines. In the 'States items like Startron, Sta-Bil blue are recommended, but I have yet to do a UK search. Ethanol fuel goes through a phase separation after 35 to 40 days, and this is why the fuel you buy at the pump has to be mixed just before it is loaded into the delivery tanker. Phase separation is where the water content in the fuel separates out and sinks to the bottom of your tank. The petroleum based additives break down the water molecules and allow it to be burnt. Check out Fuel Testers.com and look for their additive list if you are unsure as to what to use. Tracey, as to your friend's tank, the only answer is to try to remove the petseal ,clean it and treat it with an ethanol resistant coating. I feel a Ban the ethanol fuel party coming on. Write to your M.P. and let them know what is going on. This stuff is evil. ET43,
Caveat Emptor and all that it implies.