View Full Version : Will my floor hold a 300 gallon aquarium?

09/25/2016, 12:05 PM
I did some research already.. but figured what people on here think, since the experts wont say one way or the other...

I have a wide-flange metal beam (I beam) running down the middle of the house with 3 supporting jacks and it rests on the concrete foundation as well.

the joists are 10x2 spaced 16" on center... house was built in 1959.

My plan is to put the tank parallel to the metal beam, right on top of it. (perpendicular to the joists), at the end of the house, so next to the foundation. Unfortunately, that area of the basement is finished and I can't see or add any additional supports without wrecking out drywall.

the tank I'm looking at is acrylic. should weigh 2500lbs full of saltwater, so likely 3,000-3,500 including sump and equipment, rocks.

I suppose the answer should be put it in the basement with the concrete floor and floor drain. but I'd much rather place it in the living room.

09/25/2016, 12:22 PM
How much damage can you afford to sustain should the tank or floor fail? Figure this value against the cost of hiring a structural engineer and doing it properly.


09/25/2016, 12:31 PM
While I'm reluctant to give the same advice as Dave, he's right, the best you'll get here is speculation based on a base on a number of unknowns.

That said my speculation is that it should be fine. That said, if the foundation wall is crumbling (and unseen because it's behind drywall) then you can have a huge issue. If the foundation wall is strong, and the structures are strong, then the beam can take the load without batting an eye. I know the condition of my house, and what it can handle, I can't expand that onto your house.

09/25/2016, 01:08 PM
Assuming the joists are not dry rotted, warped, or damaged by water or termites, you will be fine if your beam is directly below the tank. You could run two short beams 24'' off each side of the I-beam and double up your joists to increase your safety factor, too.

09/25/2016, 01:49 PM
i had an engineer friend come in and look at my placement of my 300 gal tank before i filled it...totally level and he said shouldnt be a problem...i still had some settling and the floor did sink a slight 1/32 after the tank was in position and filled for a day...my over design of everything saved the day but I was very un-nerving filling this tank, listening for creaks and groans of the base and foundation...just thinking what 300 gallons spilling all over my lower level of my house would look like...

09/25/2016, 02:37 PM
haha.. yeah.. maybe I should just stick it down in the basement.. it's not that heavy.. 300lbs I think empty. a few of my friends and I should be able to handle it. I'm going to go take a look at it this evening.

09/25/2016, 04:08 PM
You say drywall, and that makes me think finished basement, which may change this. My 300 (acrylic, 8'l x 24"d x 30"h) was in the middle of our last house over an unfinished basement. Floor was a skim coat of cement over sand. Similar joist setup, although I was near a 96 year old wooden center beam down the center of the house rather than steel near the edge.
It may well of held, but I didn't really want to break the main supporting beam through my house and I had a heavy shelf holding 5x 20 gallon tanks on the other side of the wall.
I added a pair of 2x10's under the joists (parallel to the main beam about 18 inches away to be under the center of the tank), then put two steel jack posts under it. To keep them from punching through the floor I put 6" x 24" x 24" laminated wooden blacks and a piece of steel 18" or so from each end and tightened everything up. A line with a weight hanging near the floor from the ceiling told me how much things deflected when I filled it, I don't remember what mine moved by, but it was bordering my ability to measure the change. I also leveled before filling and made sure it was still level 24 hours after filling.
The tank was there for a less than a year before I moved out, but there was no cracking of plaster, marks in the floor, or anything else when I removed it all. The hardest part was supporting the 2x10s I added before I got the jack posts in.

09/25/2016, 04:43 PM
haha.. yeah.. maybe I should just stick it down in the basement.. it's not that heavy.. 300lbs I think empty. a few of my friends and I should be able to handle it. I'm going to go take a look at it this evening.

Oh totally, I moved a 375g acrylic with 3/4" acrylic to the stand by myself with some furnature dollies.. took a friend to push it up on the stand though... BUT have a few friends would have made it way easier

09/25/2016, 08:35 PM
Nice info there jccaclimber. I'm sure the wood and foundation is in good shape, no reason to think otherwise, rest of the foundatoin/wood looks fine. I think I will try to take it downstairs though.. I'll just have to remove a rail I think to clear a corner. and yep.. i did buy it.. It isn't drilled though.. I have been going sumpless but with a tank that size I think i'll really want/need a sump.. it does have a sump, but it uses one of those vacuum/gravity feed systems..

If it wasn't a finished basement i'd probably put in some extra support and call it good and use it upstairs.. but I just don't think that's a good idea. I'd probably be okay as it is, but like dave.m said.. is it really worth the risk? Looks like we should be seeing a build thread from me soon..

Drilling and plumbing a tank myself will be a first.. and i'll d it on a 300 gallon.. a bit daunting. I'll be watching some videos and doing some research.. bean animal style overflow I'm sure... But I suppose I'll post a new thread when I'm ready and ask for advice/tips from people. It's currently a freshwater tank so I'll need to buy a few things...

09/27/2016, 11:32 AM
If you're like me then you love your basement and want to spend as much down there as possible. Thus, it makes the most sense to put your time-sink, I mean reef, into the basement too! :0)