The sump isn't really big enough to lay them down. It has the sponge blocking the path. I had thought about cutting the sponge some, but that would allow a bypass that I don't want. It is one of these jobbies with the skimmer removed. I am going to look at the inline heaters after work today.
OK, so it was a dumb question. :hihi: You never know someone's experience level is.
A lot of folks around here give those hydor heaters good reviews. The biggest drawback to them that I am aware of is that they reduce the flow. The nice thing about a sump is that shouldn't be an issue, presuming that you have a slightly over-sized pump.
How about this: It looks like you could cut a hole through the sponge and run the heater through it. I don't know that I would do it, personally, it seems like it could be a pain, possibly ugly, and probably impossible.
And, by the way, multiple smaller heaters are a great solution, if you're ok with the cost. Usually a smaller heater is just a couple of dollars less than ones twice their size, so you'd be effectively doubling your heater budget. The benefit to this is that you reduce the risk of 'cooking' your tank with a runaway heater.