This is what I mean, The OP has good ideas, but no experience. Yes, you need to test for pH frequently. Depending on your media, the pH can change as minerals leech into the water. You may have to change media if it is too bad. The best idea is to soak your media in a bucket of water for a week or two before you fill a grow bed with it, and test the pH every few days to see if it is leeching.
There are test strips which will test all those things other than total dissolved solids (EC / minor minerals.) There is a hand held gadget that will test that for you, and give you pH and temperature - also important. You will also probably need to add chelated iron - or throw some rusty nails in the system. You don't need to test for it, it is so common that yellowing of the plants is assumed to be an iron problem.
The ammonia, nitrates, nitrites testing is how you know when your system is "cycling." It is the ni-trite / trate conversion you are looking for.
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