A few questions on the process=
Is there a difference between regular expanding foam and outdoor expanding foam?
What brand of foam would you recommend?
Does the foam stick to the glass walls of the aquarium or does it need to be anchored once sprayed on and dry?
Is there a product other than cement to coat the foam as i dont want to buy 100lb bag of cement and end up only using a pound or two.
I guess once into the spraying of the foam and applying the cement i can presumably say goodbye to this tank ever being an aquarium again?