They've never really taken off until recently when I got the PH higher.
Yes, it's one of my other tanks. It can look better than this but I don't do much in it right now.
Are your plants under a good amount of light? You need good light to grow them fast enough to mop nutrients.
Your may have lacked certain nutrients too. How did you get the Ph higher? Maybe they had lack of Mg and Ca...Emersed plants have unlimited CO2 so the only stop is light and nutrients, the latter shows deficiency signs if lacking.
Mine need supplemental dosing as the bioload is not big enough for the plants.
Ph needs to stay stable. Fluctuating or dropping ph is a sign of acidification which is normal in fish tanks due to the processing of the bioload. Water changes, plants, purigen can all help with keeping the conditions stable.
So the Nitrazorb works to control nitrate.
The best usually is mopping the ammonia before it converts to nitrate but that's hard to achieve without plants. The nitrate itself is not an issue, it's the host of chemical processes that take place while ammonia and organics are processed in a tank, which alters the chemical composition of the other in a bad way and affects the fish well being. Nitrate is just a measure of what has happened prior to that but they hardly have any negative effect on fish on it's own, and as well, it's very hard to measure accurately so what the tests show you could be way off either direction. I don't even ever bother measure nitrates ever unless I am experimenting. My plants tell me when I am out of it. Have you tried Seachem Purigen instead? It takes up organics directly rather than nitrates which will lower the produced nitrate in the end as the organics won't have to go through the whole nitrification process and others.
and Fenbendazole (in theory as wide spectrum as flubendazole) has a problem with being used in food...
All I've read about fenbendazole is that it's used in food, not in the water column. It causes head standing and death in discus fish if used in the water column. At least that's what I've read when I read about it. And I did research when I had to use it myself. It didn't do anything for hex for me, at least not fast enough.
Metro is really not applicable
I have to disagree. We don't know that and if it were me I'd certainly treat for Hex too. To me that clown looks like a long time hex suit case but then again, I haven't dealt with other intestinal worm infestations and they certainly seem to cause similar effect. So it's just an educated guess.
However, I would not have used metro to treat hex. It didn't work for me one bit on a heavy infested fish. Epsom salt soaked food did way better and fish don't reject the food, plus it's way less likely to have any negative effect on any fish and can be used in combination with any treatment. There's no adverse effects reported about it at all.