Do fiberglass tanks bow?

[Swingline77]

I drilled a 20L for a sump, and I'm not sure that I trust it's 3/16" pane thickness. I'm thinking of replacing it with this fiberglass bin ( https://www.ebay.com/itm/MFG-Tray-5...=item41c22e43ac:g:QeEAAOSwc49Y7iFa:rk:27:pf:0)

If I were to assume the outer dimensions to be the same as the inner, and the sides to be perfectly flat panels, there would be a maximum volume capacity of 33.5 gallons. Since neither of these assumptions are actually true, the volume would be somewhat less. 33.5 gallons of salt water (at 8.6 lbs/gallons) weigh 289 lbs. The stated capacity for this tank is 500 lbs. Under normal operating conditions, it would not be filled to the max anyway, to allow for overflow.

This tank costs about the same as a 40 gallon breeder aquarium. Some advantages over the breeder would be: I think acrylic baffles might bond very well to the interior compared to bonding them to glass, fiberglass is less fragile than glass, drilling might be easier, it's opacity would be nice in keeping light out (of course, a glass tank can simply have aquarium paper put on the exterior to keep light out). Disadvantages would be possible possible leaching of chemicals from the fiberglass (and I really don't know if this is a potential issue), and possible bowing (as is often seen with polyethylene tanks).

Would you use this, or a 40 gallon breeder?

Thanks

 

[Brad Miller]

Any tank will bow if using outside the mfg constraints of pressure applied from all directions...
Fiberglass is typically made with polyester resin to hold the fibers together.
Others have used fiberglass but then it became know about the leaching of resin into the tanks.
Not sure what the bin you want, would be considered reef safe or not.

If it's made with epoxy resin, that would be considered very reef safe.
Maybe someone else could elaborate further...

 

[Swingline77]

thanks