since this a freshwater forum and there really isn't a place for a saltwater reef here,I guess my tank build will be OK here as it could have been freshwater 
when I decided to build a plywood tank,I trolled a lot of forum in search of how to do it,this forum had so many beautiful plywood tanks that I referred to it very often,so here's how I built mine....
the measurements are 96" long,36" wide,and 27" tall,water level is approximately 24" deep..roughly 360 gallons,I also built the sump with left over supplies,it was as big as I could build it and still be able to fit it under the stand once it was all in my home....
I started with 4 sheets of 23/32" thick plywood(3/4" sanded on 1 side)not the best quality but definitely much better than the cheap stuff
I cut out all my panels to size and predrilled and counter sunk all the screw holes and used 2.5" drywall screws 2" apart to assemble all the panels,turning the sanded side of the plywood inward so it would be much smoother,I using a waterproof polyurethane base construction adhesive in all the seams,this made a very strong box...
I used automotive body filler(Bondo)to fill in all the screw holes and all the knot holes on the outside of the box to make everything as smooth as possible....
I then proceeded to apply fiberglass epoxy and fiberglass matting to the interior,overlapping the corners so it would be stronger....
after the 'glass work was done,I used blue Sweetwater 2 part epoxy to add the color and several extra layers of waterproofing....
here's the pics of all that
after the fiberglass
when I decided to build a plywood tank,I trolled a lot of forum in search of how to do it,this forum had so many beautiful plywood tanks that I referred to it very often,so here's how I built mine....
the measurements are 96" long,36" wide,and 27" tall,water level is approximately 24" deep..roughly 360 gallons,I also built the sump with left over supplies,it was as big as I could build it and still be able to fit it under the stand once it was all in my home....
I started with 4 sheets of 23/32" thick plywood(3/4" sanded on 1 side)not the best quality but definitely much better than the cheap stuff
I cut out all my panels to size and predrilled and counter sunk all the screw holes and used 2.5" drywall screws 2" apart to assemble all the panels,turning the sanded side of the plywood inward so it would be much smoother,I using a waterproof polyurethane base construction adhesive in all the seams,this made a very strong box...
I used automotive body filler(Bondo)to fill in all the screw holes and all the knot holes on the outside of the box to make everything as smooth as possible....
I then proceeded to apply fiberglass epoxy and fiberglass matting to the interior,overlapping the corners so it would be stronger....
after the 'glass work was done,I used blue Sweetwater 2 part epoxy to add the color and several extra layers of waterproofing....
here's the pics of all that
after the fiberglass
