50 gallon drum, how many "aquarium gallons"

[Dearth]

Originally Posted by FishyFishy!

How much live rock do you have in it? It could very well be taking up a lot of water volume inside the tank.

My 210 probably only holds 150 gallons of water with all of my live rock in there.

Oh..and internal or external overflow?

Very good explanation rock can displace a large volume of water
Half my 95 gallon tank is taken up by rock so at best I might have 50 gallons in it