Four groups moved or removed, the old rooted bases discarded, and the light measured again at what is left.
Myriophyllum 'Guyana' moved from the back left corner to the front right, where it now sits behind the Monte Carlo and in front of the Hygrophila 'Kompakt'. Its growth has been staying around three inches tall, which is what the position is for: a low, fine-textured group between the carpet and the midground.
Hygrophila pinnatifida came out of the scape entirely.
Rotala 'Blood Red' moved to the far left background corner and Rotala 'Orange Juice' toward the centre background. Both were treated the same way: the old rooted and emersed lower portions were discarded and the healthy submerged tops were trimmed and replanted. The Ludwigia 'Pantanal' group was trimmed heavily on the same principle, with the best tops kept.
A water change of roughly fifty percent followed the replanting.
Blood Red reads approximately 80 µmol/m²/s at the replanted tops, Orange Juice approximately 115, and the front-centre red group approximately 100.
The Blood Red figure is a reading of where the stems currently are rather than of the position. Freshly replanted tops sit low, and the number will rise as they grow toward the light, so it is not comparable to a reading taken at an established canopy.
Orange Juice is still growing green. Whether that changes is a question about new growth under the current light rather than about the growth that is already there.
Hair algae is still present, and very little new visible growth appeared the following day. The measure being used is clean new plant growth rather than existing affected leaves becoming clean, because affected leaves do not recover.