I’m not sure about videos, but anecdotally:
Phosphate and Alkalinity are easy and works very well.
Calcium instructions are convoluted and confusing at best. The need of distilled water is annoying and results are wildly different based on a multitude of variables. The goddamn sample water being one -.-…
Low Range Nitrate- Takes too long. Don’t recommend. If you mess up it’s let 20 minutes gone. F this kit
High Range Nitrates- works better. Less issues and places to mess up.
I would still recommend salifret kits for nitrate.
Ammonia - Don’t think it’s worth buying. You’d use it one or twice during set up. A cheap API kit would suffice with ammonia to see if there is or isn’t any in it. Don’t need precision numbers.
Magnesium had a hiccup on release with their reagents messing up. Has had a bad connotation ever since. But they released an apology and sent out new reagents free. No problem since.
Salinity Handheld is very convenient. Would recommend testing and calibrating often tho.
pH handheld I mean it’s simple and convenient. The cost is kinda high for what it is.
Master Testor - good for what it is. You still need to use different reagent and test everything separately unlike what they trying to market it as. Too expensive. If you have other kits, no point in buying.