Its very easy to size the branch circuit requirements for your tank. Let's build an imaginary tank and see what it is going to take to run it.

First add up all the Ampere ratings, if the equipment is rated in amperes.

Ballast for 2 - F60T12 VHO 2.34 amps each
ARO 175 watt metal halide ballast is 1.65amps

The National Electric Code (NEC) requires that any circuit supplying any type of HID lighting, fluorescent or MH, be derated to 80 % so divide the total amps by .80
Divide the amps shown on the name plate by the derating factor 2.34/.80 = 2.9 VHOs 1.65/.80 = 2.06 MH
use this number in your calculations. Amperes will be on the nameplate as required by NEMA and ANSI.

ok so you have 2 - 175 watt MH and 2 - F60T12 VHO ballasts = 2.9 + 2.9 + 2.06 + 2.06 = 9.92 amps

Next take anything rated in watts. powerheads, heaters etc

Power heads 3 at 35 watts, 1 power head at 15 watts, 1 heater at 200 watts, ozonizer at 80 watts etc etc

Now take all those watts and add them together and divide by 120 i.e. 105 + 15 + 200 + 80 = 400/120 =3.33 amps

next take anything rated in horsepower such as pumps/chillers etc.

1 pump at 1/4 hp and one chiller at 1/4 hp = 1/2 and multiply by 745 = 372.5 watts then divide by voltage 372.5/120 = 3.1 amps. NOTE: If you have something running at 240 volts you should calculate that separately from anything running at 120, just divide by 240 rather than 120.

Motors generally have a pretty crappy power factor if they are not running fully loaded but go ahead and use .80 as the power factor and you will be okay since they are not pulling the full amperage. soooooo 3.1 divded by .80 = 3.88 And remeber that motors and chillers have an inrush current when they start up. Although you don't have to size your circuit breaker and wire to account for this, a chiller that draws 1.5 amps may see as much as a 12X inrush when it cranks up or 18 amps, which can cause a 15 amp breaker to trip. Motors also tend to drive GFCIs a little nutty at times, too, and they will trip. This is caused by the distorted waveform when a motor starts up. Don't buy the cheapy, get a good one! The cheap GFCIs do not have electronics which ignore distorted waveforms, that's why they are cheap! A circuit breaker type is much better than the receptacle type in avoiding nuisance trips.

So now our imaginary tank has 9.92 amps of lighting, another 3.33 amps of powerheads etc, and 3.8 amps of pumps and chillers which is 17.05 amps.

Residential receptacles are usually rated at 15 amps so you would require at least two circuits. And remember that you may very well have other loads plugged into the same circuits since the NEC allows up to 10 receptacles on a 15 amp breaker or 13 on a 20 amps circuit! Everyone knows what a 120 volt 15 amp receptacle looks like, the blades look like (| |), (not showing the ground pin) a 20 amp looks like (-| |).

And BTW Brian, you cannot install 30 amp circuits for 120 volt receptacles ...20 is the max and they must be wired with 12 gauge wire Most houses are wired with 14 gauge which is good for 15 amps unless a local ordinance requires #12 for residential receptacle loads. (Many do now!)

I hope this helps and if I made any arithmetic errors...gimme a break, I am an electrical engineer, we have staff to do the arithmetic...lol