I agree. My take on Shilongba Reservoir was that it has to be better to deliver a result that is obvious quickly in order to bolster both public and official confidence in the tech in order to justify the program in an ongoing way. This also means a sense of public relief that something tangible is being done. "Hey look everybody, we are doing something about this problem, and look, it is making a huge difference!" Treating the reservoir, which is a defined and enclosed area from a water circulation perspective is a smart move. A single treatment of a defined volume of water will show better and far quicker results than one that is being flushed by significant continuous inflows/outflows, and especially so when inflows contain phosphorus pollution. Visible results can make the local TV news, making them "real". Officialdom will then be able to point to Shilongba Reservoir as a success story, and this will justify the whole Dianchi program when the results from Dianchi will take much longer to become quite so visible.
Phoslock will work on any body of water, big or small, deep or shallow, warm or cold. But the treatment will take longer to become visibly effective when the volume or scale requires either massive - and thus potentially wasteful - application rates to show a result. This potentially is in conflict with obtaining and maintaining Public confidence, which has to be cultivated at the same time, and right from the outset.
The authorities will understand that the results will take time to show clear results in the algal loading. So I would expect all of these issues will have been fully taken into account in the engineering plan.
(20min delay)