Do not use a tank sealer on aluminum. My experience is that it will not adhere to the metal. I tried it on my lakes roadster that had an aluminum tank, etched the inside etc. and about two years later I was cutting the top of the top of the tank and pressure washing large sheets of the sealer out of the tank! What a mess, I had a very large screen filter in front of the fuel pump but it was clogged too!! Hotrod is right, anodize it.
It very much depends on the sealer
there was some stuff available from 3M called EC776
they used to use inside the wing tanks on F111 in Australia. The downside being the maintenance guys had to climb
inside the tanks and paint it on. Didn't do much for their health.
you can buy it one quart tins but you need to wear a mask and gloves as it's pretty toxic.
I used to use it on alloy tanks in bikes and had no problems with it coming off