What are the opinions on Submersible heaters Vs Canister filter heaters? I love the idea of the canister filter heater since it will be hidden and don’t have to worry about where to put it so it isn’t so noticeable. But also that it will be certain to circulate the heat evenly. But it is a pretty new concept, so I worry that it hasn’t worked out all the bugs yet. So what are your opinions on this? Also I have a Fluval 404 canister filter, if I were to get a heater for this, what brand would work with my filter?