Here is my take on it. Do I recommend? No, I don't. I think it is going to come down to each individual hobbyist to answer that. Not trying to pass the buck or dance around a solid yes or no. I think it just depends on the system, maturity, and a slew of other things. There is a lot of debate on their accuracy as it relates to our water sample to include procedures, or lack there of, testing. To include calibration and cleaning between water tests / samples. A few of the fellows / professionals here who work in either chemistry (
@Randy Holmes-Farley for example) and the marine biology field (
@Thales another) have raised some talking points, or papers, on the subject. I found them great to read and educational. That all said and done I would also be fibbing if I say I don't use them. I do. I use ATI and send 2 tests a year off, maybe 3. I use them as a outside view of my water tank chemistry to check with what testing I do, do not do, and as a reference. That is it really - I use it as a reference because I'm lazy. Tank maintenance is not fun for me. Not going to lie.
If so who should I go through? I am biased and use ATI. I would recommend them. Great support. Friendly. I get consistent results. They answer emails timely. They seem like they have a good handle on it. So they are my preference. IF you ask who I would recommend they would get my vote.
How often should I test? Up to you. I send off 2 or 3 a year. No more and I don't see a reason to. If you are balling or doing something like the triton method then I can see people sending in more frequently. 2 is my number 3 if I am chasing something.
How long after starting a tank should I wait? I wouldn't think you need to do anything anytime soon after the cycle. I waited a year before I sent mine off. It just depends really.