Yup, thanks for the link to the exact product very helpful. I have a HDPE (plastic) tank with improvised walls made with plastic bonder. Would definitely go aluminum next time.
I don't have as many kW to cool as you yet, but I'm just using a 20"x20" water radiator + fan, rated for 190k BTU assuming sufficient airflow. radiator
Note that I don't know how well this actually works yet, but in theory you could get multiple of these with fans outside and eventually have enough heat dissipating capacity. I'm not an engineer by any stretch, so there's probably a better way especially considering your scale.