I am building a 78''x36''x30'' plywood tank and was wondering if using a product called Max ACR epoxy would be an ok option or if i should bite the bullet and pay the price to get pond armor. If pond armor is the way to go anyone know how much id need to cover that size tank? I see a gallon is like $200 on amazon and really dont wanna spend a fortune on just the sealant. Thanks for any info.