Yep. The heaters hit hard. Short version is this:
A typical single pole 20 amp (20/1) circuit breaker like you'd find in most home panels is capable of delivering 20 amps at 120 volts.
(NOTE: Different parts of the country use different sizes of breakers for residential applications. Most are 20 amp but some are 15 amp. You'll want to check to see what's in your electrical panel. It's normally written on the end of each breaker's switch handle. If that doesn't make sense be sure you don't take the cover off... just open the door).
In a residential circuit the available wattage from that same breaker would be amps x volts which in this case is 2400W... theoretically. There will probably be a little bit of voltage drop and a little bit of resistance and some other voodoo in the circuit which usually makes it a good rule of thumb to figure that you have roughly 2000 watts that you can reasonably work with on each 20/1 breaker.
The way an inline aquarium heater typically works is that it is on or it is off. It can't sense that your water is just a degree or two shy of the 84*f you aimed for so it can just come on a little bit. Instead, as soon as the thermostat senses that the temp is low it comes on full throttle and shuts off when the appropriate temp is reached.
That means that there are a couple things to keep in mind w/ a big tank like yours. In my mind those are:
- If you have 4 ea, 500W heaters on the same circuit and they all come on at once... that breaker could trip and you may not know it for a day or two. It may not be a big deal as you keep your house w/in the 'green zone' of most tropical fish thermometers.
- If you have the above come on as described and there's something else on that same circuit the problem gets worse.
There's also something called the Inverse Time Element that basically means that a 20/1 could see 25 amps of draw for a few minutes and might not trip but if it saw say, 50 amps of draw it would trip quickly... so there's a little bit of wiggle room in there and it does help minimize nuisance tripping but it's not something you should normally bank on working in your favor. If anything you can suspect that it may not always trip at the same time under the same overload conditions.
The other thing that you want to at least think about for a moment is heat storage mass. You have stepped up to a very large tank and when you do that a question comes up about heat and how you might want to think of it. For example, let's say you currently heat your house w/ a natural gas boiler and it's super efficient and it keeps your house at 73*f non-stop cost effectively. You're about to be heating your fish room with electric heaters as that big tank will be far hotter than you keep the rest of the house. It's not a huge deal but it's worth thinking about for a moment. If for example the only thermostat for that house is in the same room the big tank is in and the rest of the house seems to be cooler than you like... it's because the heat from the tank is high enough that it never tells that t-stat to send heat.
I had smaller tanks for decades. Never anything bigger than roughly 220 gallons. When I jumped up to an 800 though a few things changed that I never had to think about before. None of them bad but there was a thicker layer of complexity that I hadn't given much thought.
As far as LED lamps go I would suggest an outdoor rated lamp. They're usually called PAR lamps and the choice between a spot light pattern or a flood light pattern will be part of that voodoo you want to sort by deciding how high above the tank you want the fixtures, etc. I also wouldn't spend an extra nickel on any LED lamp that advertised that it lasted longer than the others. The truth is that you're going to want to do something different in a couple years and spending extra for a lamp that brags about being good for 25 years is not going to have been worth it. It's also true that LED lighting standards are a little different than you or I might expect such that in ten years that same screw-in lamp may only be putting out half the light it did when you bought it but the LED mfg would tell you that it's still fine. A lot of the LED mfg's are selling efficacy specs that mean something different to you than it means to them. Buy a cheap outdoor rated LED lamp of the highest reasonable wattage equivalent (something that says it puts out the light equivalent to a 120W or 150W incandescent should be pretty darn bright). Bonus if they're dimmable as you may find you want to mess w/ light output as well and some aren't dimmable.
Then you may notice a cave effect where it's light within the pattern but not uniformly so within the tank. You see that clearly in the DIY guy's vid. Next thing you know you'll be fooling w/ height adjustments and similar but you'll nail it. Just takes a little fiddling.
He said he designed it to be extremely user friendly as far as setup.
