It's a misconception that makes very little sense if you think about it. 1. Where would the air come from when surrounded by nothing but water? 2. What would happen to the fish if it suddenly became full of air? It would shoot to the surface at about 100mph and then bob around like a buoy.
Ah, still use mah career pidjuns and thet's the way ah lahk it! Ah don't need none of these new fangled telegraphamajigs!
Hehe, I haven't yet bought a cell phone, actually. All mine have been hand me downs from the wifey.
If you can, I'd eliminate that heater section and have it in either the pump area in the fry area. Assuming everything is to proper scale it looks like it should fit at an angle. There's just not really any good reason to have the heater seperated.
As far as a 12v supply for the fans, if you don't have a 12v wall wart laying around how about a 50w 12v halogen lamp ballast? They should put out 12v(One would imagine ) and you won't come anywhere near its capacity with a couple of fans. They're pretty cheap too, I picked up a 110w one for $14.
If you wire it into the mains plug that powers the lights and can hide it in the hood it could give you a much tidier installation than having a second wall wart plugged in alongside the lights...Cut down on spaghetti a bit.
Is it a slow blow or fast blow fuse? Needs to be slow blow otherwise it will go when you turn the light on due to the high current surge at they start.
I'm not sure why the concern over single vs tandem axle trailers? The suspension in both would be extremely stiff given that they're carrying 0 weight and the spring rates would be specced for carrying a lot of weight. But I'd think the tandem axles being generally higher weight capacity would be stiffest?