Loaches Online Forum

Hi there,

I am hoping some of you more experienced aquarium owners, and/or people who are better at math than I am, can give me a guestimate to how much a fully setup 75 gallon tank would weigh?

We are upgrading our smaller 36 gallon tank and would like to put it our sunroom, which was an addition to the house and is over a crawlspace - not our basement. The foundation and floor joists are not as beefy.

I'd like to avoid having a fish tank fall through to the crawlspace if ya know what I mean.

Haha, I'm fine with reinforcing the floor if need be. Just wanted to know if it was necessary. We have X amount of weight in here right now in furniture so I'm curious to know how it would compare.

I don't know how accurate this is, but it will give you a good ball-park figure:

http://www.aquariumlife.net/galcalc.asp

75 USG of water alone weighs about 626 lbs.

Your determining factors will be heavily based on stand type and design. What is weight capacity of existing joists and where does their location line up with the location you desire for the tank? A four-legged steel stand puts all that weight into 4 small areas whereas a cabinet stand may spread the load over a far greater area.
Once you know this kind of stuff it's still advisable to get a structural engineer to check it out before commiting to it.

Martin.

Unless your floor is on a concrete slab...in which case...go nuts.

Still wish I had a basement.

always guess higher than need be.
I would go underneath in the crawlspace and re-enforce it.
that way you can go to a 125 or 250 gallon

This is a good reference for sizes and weights:

http://www.thekrib.com/TankHardware/size-chart.html

cheers,
wm_crash, the friendly hooligan

Measure the distance between the joists, should be either 16" or 24" on center which would give you about 14.5 or 22.5 between them. 16" on center is stronger. Also measure the width of the joist boards. Hopefully they'll be 2x10 which would measure 1 1/2" x 9 1/4 roughly. If you have 2x10s on 16" centers and you put the tank against an outside wall, or a wall with a bearing wall below, you should be fine. But it would be a good idea to have a carpenter or engineer with such knowledge have a look. Martins' point about distribution is important also.

You can get a reasonable ballpark of the weight by multiplying the (American) gallons by 10.
75 gallon tank plus stand, water, decor... 750 lbs.

Metric: liters = kilos, then add 20% for stand, the tank itself, rocks...

Yes the rocks and gravel are displacing the water, but they are heavier than the water that they are taking the place of.

I would keep this size tank against a structural wall, over a foundation, or reinforce the support.
Over a crawlspace might allow you to add a couple of piers and some lumber that would beef up the floor. Better safe than sorry!

Thats 250 pounds per square foot .About the same as a large person standing on the floor if your stand spreads the load evenly. If it has 4 feet the load is not spread evenly it would be about 200 pounds on each foot.

Thanks for the input. Because of the information and advice you have provided we are going to have our contractor take a look underneath our sunroom AND the main living room... just so we have options for the tank. Better safe than sorry.

Who knew fish could be so much trouble?