gas tank overhaul

i don't get to use my boat as much as i used to. i had some water accumulate in the gas tank so i pulled the tank and emptied it. while it's out are there any other preventive items i should do? i've never opened a gas tank before.

i ordered a new fuel sender from WEMA that's supposedly much more accurate.

is there anything to the pick up i should/can do?

does the tank need to be flushed out? i drained about 6 gal. into an old red gas can so i'm not really sure how nasty the contents were.

is there an additive that will help? i've read about startron supposedly being good.

You can take it to a radiator shop. They can boil it out and seal the inside. Boiling it clean is good to have done, sealing only if you suspect leaks.