Prepping for the move to the outside tank

Maybe 3 people will ever read this.  Huzzah!
So, the IBC is full of water, and the heatwave we're experiencing is really helping by increasing the temperature of the water.  Now, I have to come up with a way to maintain the heat.
1 - Insulation!  I will surround it with an inch(ish) of styrofoam, including the top, and leave a hatch for feeding
2 - Heating!  this is the problem.  The fish will smash any glass heaters, the heaters will melt the side of the IBC, so what do I do?  At the moment I'm thinking about floating a glass heater with it's plastic guard in a piece of styrofoam.  My hope is that would be sufficient: one 300 watt heater.  With the insulation, it should be sufficient, right?

I realized yesterday I can move one or two first, lowering the nitrogen pressure on the downstairs tank, and literally testing the waters of the outside tank.

This may still work!