I like that you put lazy and cheap in the thread title, because that describes my approach to hobby perfectly. For years I had a fish only tank and was satisfied with that. I wasn't interested in a reef tank, mainly due to forums like this. Don't get me wrong, I love these forums and have used them to learn most of what I know about marine aquariums, but you don't need to read more than a few threads to figure out how costly and time consuming the hobby can be.
Then I got a chance to buy a much larger tank and a really nice stand pretty cheap, so I went for it. I already had a sump somebody gave me, and live rock in my fish only, so I thought, "Let me see how cheaply I can build a reef tank". I joined some local reef communities on Facebook and found a lot people selling their outdated equipment for a fraction of the original cost. Over the course of time, I acquired the various items I needed either really cheap or sometimes even free. In the end, I had a pretty decent 125G complete setup for less than $1000.
My lights are the only thing hooked up to a controller. I just set it and forget it. I connected a waterline directly from my RO/DI to a float valve in my sump, so I don't have to haul water for top offs. I change the RO filters and DI resin about once every 6 months. I replace the membrane about once a year. I throw away a few handfuls of macroalgae every so often to export nutrients. I do a 30G water change about once every 3 or 4 months or if things start to look bad. If things start to look really bad I send water samples to a lab to for testing, and make a reasonable attempt to correct whatever issues the tests might reveal. That's the full extent of my maintenance. I don't dose, and I don't even own a test kit. You can't get much lazier than that.
I don't spend too much on livestock. I don't think I've ever paid more than $60 for any one item. Some corals grow, some die, and some never change much. Ultimately I've wound up with mostly the types that do well in less than ideal conditions, like mushrooms, leathers, and GSP. Those that some might consider invasive. Candycane is the only type of stony coral I've been able to keep happy, so I'm not sure it's technically even a reef.
All that said, I'm extremely happy with my tank. Except for an overabundance of starfish, it appears to fairly well-balanced and healthy. It's definitely more colorful than my fish only, and you never know when something weird you've never seen before will pop out of a rock. That's the part I really enjoy.
So that's what you can expect from the cheap/lazy method. While it's certainly not state of the art, it can be pretty satisfying, as long as you're not looking to create a pristine environment.
No dosing, reg water changes with tap water and I only test for Phosphate and Nitrate.
