I’ve really been thinking about doing the whole Apex thing because I really want Trident. But reading all the posts here on BAR about them makes me think they’re hot garbage. I wish there was a better alternative.
I have found that there def some modules that are better than others for sure. I do like the trident. I find it useful in guiding small dose increases up/down.
I use AFR so abrupt changes are not apparent but with 2 part I could see how for example-a build up of alk solution precipitate could block the line suddenly dropping the reading a bit.
Calibration is needed every couple months IMO and worth doing to keep the readings relatively accurate -and I mean relative..
Reef factory does have some new self calibrated testers for various elements that include alk, ca, mg, PO4, NO3 that look promising.
However on the face of it-a tester costs ~$600 and can be used for only element at a time. Also does not look available in US but could be wrong.