Very common issue with clay suspension.
The first thing to do is find the cause. Is it mechanical disturbance-something causing it, such as wind/wave action working on the shore, dogs swimming in it, etc.. or is it really suspended clay from the basin not settling out.
The rising of the material is not unusual. It's flocculation-colloidal clay particulates that "flocculate" by means of the agent you are clearing the water with.
I don't remember the exact chemistry but I believe Alum has negatively charged ions that attract and combine particulates and sink them-eventually.
When using Alum you have to be careful of the pH before you begin because Alum is acidic, so to counter this you can run/dump/pore Hydrated Lime into the Alum treated water as a buffering agent. Here's the plus with that...Hydrated Lime (Calcium Hydroxide) has 1 additional negatively charged ion, adding more clearing power to the Alum and a very stable pH. General rule of thumb is use Hydrated lime at 50% rate of Alum, but depending on your average pH, you may not need that much.
If you are serious about clearing this up, we need to get to the bottom of the cause, which you pretty much have if it settles in the Jar test or not.
Figuring the total volume of your pond is very important in getting the correct ratio.
I've used this in my main pond several times and just treated one of my growouts yesterday.
Take a look at this thread...
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=124005#Post124005
