water proffing cement and silly cone accrylic bonds

[ActinopteryGuy]

Im currently building many large (8'x4'x4'+++) for my work. The base is made of cement, with rebar, and has angle bar to hold the window in place. The cement has two coats powerbond, and two coats of epoxy paint, yet we still have some leaks. not to mention the leaks at the window joint. We have tried everything including putting tile at the lip of the tank where the cement and steal connect, and adding strips of plastic on the window joints secured with sily cone and there are still leaks. We are even trying to fiberglass the bottom of the tanks to help seal them. If anyone has some insight to this problem I would love to hear as it is stressing me out.

 

[RicksReefs]

is the window glass or acrylic? silicone doesn't stick to plastics/acrylic to well.
pull any plastic off, pull the window out, clean and acid wash the tank. add a coat of fiberglass resin to the entire tank, inside and out (cement needs to be fully cured, about 3 weeks), then (preferably with the tank face down), clean the glass edges with alcohol, place silicone into the track made for the glass window, place window into the track, then once in place, do not touch or move for 48 hours. once filled, water pressure will push against the glass helping with the seal.

I'm available for house calls.

 

[ActinopteryGuy]

lol yes drop by Im located in borneo. lol
it is acryllic.