80 Gallon tank. parallel to joists. Will it hold up?

[munkyboy111]

Hello fellow reefers,

I have my eyes on a Deep Blue Professional 80G rimless "frag" tank (48"L x 24"W x 16"H). The only feasible spot in my house to put it unfortunately is parallel to floor joists, mid span, and all of the weight will be on only 1 joist. Below are the parameters of my flooring structure:

• 2 x 10 solid wood joists (species unknown, no markings, but house was built in 1941)
• 15 foot span from foundation wall to center I-beam
• Tank will sit pretty much dead center on span

The tank-bearing joist has 3 adjacent joists on either side of it. The first is the traditional 16" o.c. The other side of it has 2 joists, with spacing for the utility lines (hvac, electric) the closest joist being 13" o.c. Note that this utility spacing has a partition wall directly above it.

I've attached photos that will hopefully help visualize better than my description.

I would like to have the 80 gallon display with a 40 breeder sump underneath the stand, but can get creative as the basement is unfinished. I can potentially set up the sump in the basement.

My question is, how should I brace the flooring to accommodate the weight of the tank on the single joist? I have a unique situation as the hvac supply line happens to be right in the way of everything (see graphic, and picture). I was thinking of blocking between joist every 12" between the tank-bearing joist where I can gain access, as well as placing 2 - 3 jack posts directly under the tank itself (1 at each corner, 1 at the center) on the tank-bearing joist. Sistering joists to all affected areas I know would be ideal but not easy at all because there are electrical lines, hvac supply and return lines that run perpendicular to the area which is not pictured, making access very difficult.

Would this be sound? Or should I just forget about the 80 and go will a 40B, 29 biocube. I know that technically I should consult a structural engineer, but I figured I would start on here first.

Thanks for any input.

Joe

 

[Breakthecycle2]

An 80 gallon tank weighs nothing in relation to the floor supports.

 

[munkyboy111]

Thanks Breakthecycle2. But I'm all about overkill. Don't want any sagging considering the orientation, or worse, coming home to a hole in my living room...

 

[Breakthecycle2]

I have a 200 gallon sitting in my living room. I only know that it's against a wall with an I beam. I don't feel, if it should happen, that the floor will just go. You would notice it way before. That 80 gallon tank weights maybe 200 empty. Water weight is 8 pounds per gallon, so that's around 640 filled to the brim with 80 gallons of water. Rock will displace the water as well as sand, so realistically, you are around 70 gallons, so that would make 490 pounds, plus 200 empty tank weight, plus 60-80 pounds of live rock and 40 pounds of sand. Grand total of around 800 pounds. Thats the equivalent of having 4-6 grown adult man standing on your floor at the same time.

 

[Lynn52]

That's how I justified it to my husband when I upgraded to a 125 the excess weight was no more than 3 of my cousins sitting on a 6 foot sofa.

 

[Lynn52]

If the HVAC is under the joists not between them, you can put blocking between the joists to transfer some of the load to the next joist on either side.

 

[munkyboy111]

Thanks for the responses. The only difference is the dynamic'ish, or temporary pressure exerted due to 3 grown men over a short amount of time (taking into account they will shift around, get up, leave, etc) vs a more constant, static pressure of a tank in the same spot over an extended period of time. I apologize beforehand to any engineers for the previous description... If the floor is undersized, it will for sure flex and sag, and could ultimately over fatigue the building material. Almost like the idea of a new bed. You lay in a new bed and once you get up the bed will go back to OEM shape. Over time, the bed is bound due sag due to 8 hours of weight in the same spot per day, except in this case, 24 hours of same weight in the same spot.

 

[munkyboy111]

Kind of a bad comparison because obviously building materials are much stronger, and yes my house has been standing for 74 years. But again, I want to approach this situation with utmost caution.

 

[munkyboy111]

Lynn, that would be the plan. To block on both sides of the "tank-bearing" joist. So if the tank-bearing joist is "B", I would place blocking every 12" or so between A-B, and B-C.