I bought a boat that has been sitting for two years and my racor filters are plugging up, so I pumped out the remaining gas and looked into the tank. It has algea on the bottom and a few inches up the sides. The tank now is bone dry and I took a small wire brush and scrubbed the sides and the bottom it is 95% clean. But this is only 1/3 of the tank because I can't get past the baffels. The algea has turned mostly white. If I let it sit open and dry will this kill the algea? Will it come back to life if I put gas back in? Is there some sort of additive to prevent this? This is a gas engine not diesel.