I don't claim to be any sort of eyeball identifier of pests, but I would not assume these are dinos.
It might be cyanobacteria, or a mix of stuff.
Pushing it around might help, short of a microscope. Snotty is dinos. Cyano is not typically like that.
If this were my tank and especially if this stuff is snotty, I'd raise nutrients. I'd also remove as much as possible by sucking it out, no matter what it is.
Both of the nitrate and phosphate levels fit into my recommendation to raise them, whether there's a pest problem or not. As one can see from the posts above, not all agree.
https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/
4. What targets seem reasonable? Of course, that depends on all the other factors at play, such as types of corals, availability of ammonia, particulate foods, etc. However, for a mature mixed reef, this would be how I personally would run it:
- Let nitrate float between 5 ppm and 50 ppm. I’d use gentle export in this range, such as growing macroalgae.
- Above 50 ppm, I’d begin to focus more on reducing it, by organic carbon dosing, turf or macroalgae, etc.
- Below 5 ppm, I’d begin to dose ammonia or feed more. The target level might drop lower if dosing ammonia, just like the heavy in/heavy out scenario where nitrate may not be as needed.
- Let phosphate float between about 0.06 ppm and 0.3 ppm. This range is higher than I’ve recommended in the past. I’d use gentle export in this range, such as growing macroalgae.
- Above about 0.3 ppm, I’d begin to focus more on reducing it, by turf or macroalgae, or a binder such as GFO or lanthanum (has its own risks to tangs). If a binder: GO SLOW. Turf and macroalgae will typically be slow enough.
- Below 0.06 ppm, I’d begin to dose sodium phosphate or feed more to get the level up.
