So... I'm having some problems trying to get these two types of clusters via Aetherial Reduction and fishing. I know exactly what types of fish yield these clusters, their time windows, and how to get them. But their collectability seems to be completely random.

For example, when I catch these fish I have patience up most of the time since they all require a "mooch". This leads me to get an "HQ" fish with 8/8 purity which is way too high for clusters.

"OK" I said. I'll just wait for Patience to run out with the fish still hooked and then cast it so I can get a "smaller" fish. The results were several 7/8 purity fish, still too high.

As a last attempt I to dropped my perception all the way down to 198 and gave the above method some more tries. Again, 7/8 purity fish. Only once I got a fish that yielded me clusters (2/8 purity).

So... am I doing something wrong? Or is that really it? RNG?

If so I better get back to MorDhona and collect clusters the old way.