Thank you Rega! I haven't made a video but I can give it a try with my Canon 7D and see how it works. Always nice to learn something new
I check my values every month when changing my balling and they are usually within "normal" recommended levels.
I hardly ever measure nutrients in the water but adjust feeding and vodka/vinegar/sugar dosing according to visual ques. I use activated carbon and phosphate reducing media that I have in a filter sock where the circulation is good in the equipment department. I change these approximately every 5 weeks. I also use Ozone through my skimmer to kill pathogens, increase ORP and getting rid of the yellowing organic compounds and thereby increasing the light penetration in the water. I usually vacuum the sand when doing water changes (ca 10% per month).
I used chaeto the first year but I have now turned the refuge into a nano with fluorescent species which looks quite nice in the evenings and it is nice to inspect the corals here close up (hard to get good shots). I did not see added benefit from the extra nutrition export from the chaeto once the system was stable and I have never aimed to have a very nutrient poor environment for my corals and I think they appreciate that

. Although chaeto is quite safe compared to most other macro algae I believe they can release chemical compounds that can deter the growth in corals and stony corals in particular (more studies/understanding needed).