Dynamic tank will not draining fluid from the pipe network if the tank is at its full capacity.

if(doFill)
{
dynamicTank.structure.fluidStored.amount = getCapacity(); << This will cause subsequent call for getNeeded to return 0 thus making infinite fluid.

if(getNeeded() > 0)
{
    MekanismUtils.saveChunk(dynamicTank);
    updateValveData(true);
    dynamicTank.sendPacketToRenderer();
    updateValveData(false);
}

}

return getNeeded();

This can be fixed by storing getNeeded() in a variable before setting fluid amount to tank capacity.

I am also experiencing this problem whereby a dynamic tank that I have completely filled, when connected to a pipe network with other devices, becomes an infinite source of it's contained liquid.

Fixed, thanks!