Yes and the redsea did better for me some of the api were a little off also I took it to the pet store and they used a different test kit and theirs and mine were closer to each other .
They are good for testing the end of your cycle period and random ammonia, nitrite and nitrate tests. Which I never do..... Invest in some decent tests like Salifert or Red Sea Pro tests for your Alk, Cal and Mag you'll get better and more precise results with these kits than an API kit.
Api test is terrible for phosphates, other than that, no problems. The kh test was always +.4 for me though, which isn't a big issue. Go with red sea though, much more accurate.