Hi Norm
Hopefully that should be enough weight to hold the tank down.
I know a 1000 litres of water is 1 ton ,so if this tank had no air trapped in the top and was full it couldn't float.
1 ton of cement I think is 415.54 liters ,so that's a bit more concrete than two / 44 gallon drums to hold down
an empty tank.
Besides the weight problem on top of the tank previously not holding the tank down ,I don't think this tank can be filling
at 100 percent as it doesn't look like there is a bleeder valve (vent valve) at the top and the filler hose is not
at the top so I think air will be trapped at the top of the tank which is why this tank was floating when full.
As we know a full bottle of water sinks in water but air trapped in a bottle will have some buoyancy .
Cheers
Max.
