Both shows are entertaining if you like looking at all kinds of fish and some pretty incredible/unique custom built tanks. Both companies also absolutely know what they are doing too.
Unfortunately, because of the producers on Nat Geo and Animal Planet- the "content" of the shows have caused both of them to take a lot of criticism from hobbyists and some industry well knowns. Most likely from practices and procedures shown on the shows which do not fit what most hobbyists know & see to be good practices. The fact is the shows are for entertainment. The producers create "scripted" episodes for the people to follow to make it "sellable" to viewers in their opinion. To have a show, the companies have to comply with the created and funny stuff the producers want. The jobs and customers are 100% Real. But much of the content is created for the show so it's funny and more interesting.
Things are not in reality exactly the way it's shown on the programs. Some of the stupid and ridiculous things that are done, happen on purpose for created drama on the programs. Much of the real work is left out as all episodes filming are spliced together and some stuff is made up that didn't really happen that way in reality. Not really how the companies operate in real life. Nor would they suggest some things to potential clients in reality either.
All their clients are high end that spend huge money for custom fish display tanks and both companies are very successful. It's all about fish tanks for them in reality. They do create living reef aquariums too. However, most of their client base are those who just want to look at their incredible tank and at the most just feed fish. Thus fake inserts are most common and a specialty. Most clients also get maintenance done for them via contract.
ATM as the program "Tanked" portrays, is headquartered in Las Vegas. However, the company is quite a bit larger than the show leads onto. They have ties in Europe and an actual ATM division in Asia. They take on roughly 200 projects per year and those on the tv show are just a very small fraction of their actual jobs. They've been attending Reefapalooza and Macna as well as other convention events around the country to get the public to see a clearer picture of them in person. Not exactly what the show portrays.
I would take things you see on the shows with a grain of salt. No pun intended. It's entertainment period. The companies are legit and not as stupid as the programs may make them look with some of the artificial content. That being said, I think the shows are fun to watch. I wouldn't follow any episode on how to set up a tank or maintain it in the hobby world. They are not attempting to show that on the programs. Just entertain.