Well I did a final sanding of the plywood tank. In the next few days I will start to seal it. I've decided to go with Drylock which I got at the home depot. I read in one forum where a guy used it straight on his plywood DIY tank and it lasted a year. He didn't use it after a year because he had built a bigger one but it had not leaked at all. My tank does not have to last forever so I am going to give the drylock a go and see how well it works. It does say it is safe for fish on the product, that I made sure of.
sorry no pics but I can't afford a camera right now