RHINOMAN: I estimate your monster size concrete fish tank will hold about 1500 gallons. With good lighting and plants, the aquarium will be a thing of beauty.
The 1-1/2 thick acrylic window you are considering for your aquarium may be more than you need. Todds 72 by 32 windows are ¾ acrylic and although only 6 feet long, the addition of two more feet in length will not materially change the pressure per square inch. I know of a large Plexiglas aquarium measuring 8 by 4 feet by 4 feet tall using ¾ material, which bowed a bit in its original location with a 44 water level, but presented no problems. This same aquarium is now in my basement however cut down to 32" high in order to pass through the doorway. There is almost no bowing in this 18-year-old aquarium. I think 1 acrylic should be more than adequate however, you must check this out on your own. Many suppliers of both glass and acrylic material for large aquariums automatically recommend larger thickness than may be actually required in order to avoid damage claims due to breakage.
Your proposed very large 4 foot by 6-foot aquarium filter chamber should be more than adequate. Depending on how you engineer your fish tank filter it may be more difficult to service than you planned. Further once set in concrete it will be almost impossible to alter the design or add more piping through the aquarium walls. Carefully measure the overflows against the volume of water you plan to circulate. A slight increase in gallons per minute through the filter might result in a one or two inch rise in aquarium water level. For example: I pump 4,000 gallons per hour out of my 3500 gallon outdoor aquarium, through an Aquadyne 4.4 bead filter and back into the tank. The overflow from the aquarium tank into the pre filter sump is 4 in diameter. At this 4,000 GPH flow rate the aquarium water level drops 2 when I turn the pump off.
The installation of the acrylic windows in Todds jumbo aquarium was quite easy and we did use Silicone as the sealant. The ¾ thick acrylic aquarium window fit nicely into the 1 recesses in the concrete. This made a nearly perfect smooth edge; fish swimming along the front of the aquarium do not encounter any protruding acrylic. I recommend you allow plenty of time for the silicone to cure a week or more depending on how thick the silicone seal is. The label on the tube might give the impression that 24 hours is an adequate cure time but that is for a small thin bead along a shower stall for example.
Be sure to keep us monster fish keepers posted on your progress. What is the thickness of the acrylic you selected? Where did you purchase the aquarium window and what is todays price per square foot for acrylic? As I recall Todds ¾ thick, acrylic aquarium windows cost about $20 per square foot when gasoline was $1.50 a gallon and oil was under $47 a barrel.
We all wish you the best of luck and success constructing your concrete aquarium.
This is a photo of my temporary 3500 gallon outdoor heated aquarium:
This orphan Pacu was 12" long 4 years ago and now is 40" long and weighs 45 pounds...
Link to more heated outdoor aquarium construction pictures:
http://www.anythingfish.com/images/Ted/PhotoGallery/Ted's Outdoor 3500 Gallon Aquarium.htm
The 1-1/2 thick acrylic window you are considering for your aquarium may be more than you need. Todds 72 by 32 windows are ¾ acrylic and although only 6 feet long, the addition of two more feet in length will not materially change the pressure per square inch. I know of a large Plexiglas aquarium measuring 8 by 4 feet by 4 feet tall using ¾ material, which bowed a bit in its original location with a 44 water level, but presented no problems. This same aquarium is now in my basement however cut down to 32" high in order to pass through the doorway. There is almost no bowing in this 18-year-old aquarium. I think 1 acrylic should be more than adequate however, you must check this out on your own. Many suppliers of both glass and acrylic material for large aquariums automatically recommend larger thickness than may be actually required in order to avoid damage claims due to breakage.
Your proposed very large 4 foot by 6-foot aquarium filter chamber should be more than adequate. Depending on how you engineer your fish tank filter it may be more difficult to service than you planned. Further once set in concrete it will be almost impossible to alter the design or add more piping through the aquarium walls. Carefully measure the overflows against the volume of water you plan to circulate. A slight increase in gallons per minute through the filter might result in a one or two inch rise in aquarium water level. For example: I pump 4,000 gallons per hour out of my 3500 gallon outdoor aquarium, through an Aquadyne 4.4 bead filter and back into the tank. The overflow from the aquarium tank into the pre filter sump is 4 in diameter. At this 4,000 GPH flow rate the aquarium water level drops 2 when I turn the pump off.
The installation of the acrylic windows in Todds jumbo aquarium was quite easy and we did use Silicone as the sealant. The ¾ thick acrylic aquarium window fit nicely into the 1 recesses in the concrete. This made a nearly perfect smooth edge; fish swimming along the front of the aquarium do not encounter any protruding acrylic. I recommend you allow plenty of time for the silicone to cure a week or more depending on how thick the silicone seal is. The label on the tube might give the impression that 24 hours is an adequate cure time but that is for a small thin bead along a shower stall for example.
Be sure to keep us monster fish keepers posted on your progress. What is the thickness of the acrylic you selected? Where did you purchase the aquarium window and what is todays price per square foot for acrylic? As I recall Todds ¾ thick, acrylic aquarium windows cost about $20 per square foot when gasoline was $1.50 a gallon and oil was under $47 a barrel.
We all wish you the best of luck and success constructing your concrete aquarium.
This is a photo of my temporary 3500 gallon outdoor heated aquarium:
This orphan Pacu was 12" long 4 years ago and now is 40" long and weighs 45 pounds...
Link to more heated outdoor aquarium construction pictures:
http://www.anythingfish.com/images/Ted/PhotoGallery/Ted's Outdoor 3500 Gallon Aquarium.htm
