Checking my blogs, I saw that back in 2008, I added up what it cost to run my reef electricity-wise: 

https://melevsreef.com/index.php/blogs/cost-running-reef-tank-measured

I'm positive I did another such analysis with I got the 400g running, but I can't seem to find that article.

It's 2023, a lot of gear has changed and I wanted to see what each piece of gear is pulling in watts, and then calculate how long each component runs per day to determine what that is costing me monthly.  There are other ways to simple measure groups of items, or even an entire circuit, but I prefer to know what every plug is consuming.  There are 50 different pieces of equipment plugged in to keep all my aquariums running.  Here's the breakdown, starting with the 400 gallon reef. I used a Kill-A-Watt device to measure anything that had a plug.

Lighting continues to be the biggest consumer of power, and I needed to calculate the wattage of the three SKY fixtures I have running over my reef that go through a dusk to high noon and then taper off. With that programming, the wattage would start off lower in the day, rise as the intensity reaches its peak, and then drops off over a period of hours:

Each light uses 1026 watts per photo-period. I use three lights, so their combined usage is 3078 watts.
 

The return pump is another piece of equipment that can pull significant power, but years ago I switched to the Abyzz a200, which tends to use 160-165w of power.  160 watts x 24 hours is 3840 watts. 

 

Below is everything my reef is using, and the total cost is explained near the bottom. The Mp60 pumps use a varied flow rate, so the power peaks at 43 watts, but will slow down to a mere 8 watts at times.  I calculated running each of those at 43w 24 hours a day.  *Snapshot* is all the wattage added up at the exact moment I measured the running equipment. Each piece of equipment was carefully calculated for the actual hours it ran per 24 hour period.  For example, the pump for my top off runs about 16 times a day for a few of minutes; that equals 45 minutes runtime during a 24 hour day. My heaters tend to run once a day for an hour and 20 minutes. Some days they don't turn on at all.

As you can see, my lights cost me $4.62 per month, and my return pump costs $5.76. Those numbers were included in the $28.57 total.

 

I also measured the saltwater mixing station, which has a Vectra m2 pump for circulation / pumping, and a couple of heaters that I plug in only when I'm about to use the water. The pump runs at the lowest speed daily, using 24 watts.  But one day a month, it runs at 88 watts with both heaters plugged in, so Mixing Day wattage was included below:

 

The Frag tank uses standard gear, and below shows what each item uses:

 

The Anemone Cube is currently using a Sicce pump, a Kessil a360, and a Vortech pump.

 

Caitlin's Reef was also measured. The heater runs an average total of 1.2 hours per day, usually in 11 minute bursts:

 

My dollar amounts may look low to you, as your kWh rates are likely higher.  I have a contract with my energy supplier that locks the price at $0.05 per kWh for another two years.  If you were to compare my kWh usage with your own rate in your area, you can conclude what it would cost to run my tank where you reside. But this is why I'm happy where I live, as most things are more  affordable. So here's the grand total to keep all the aquariums running in my home, per month:

Annually, that adds up to $453.36 in power consumption for all the gear. A decade ago, that price was around $65 a month, due to equipment I used and the electricity rate I was paying. 

If you'd like to watch the video where I discuss this thoroughly, here's the link: