Jobes and other like ferts have NH4 and urea added to them.
If they get into the water column you will have an algae bloom, espeically with higher lighting.
This can happen when you uproot plants and forgot that you have them down there etc.
Therefore, if you chose to use them, you cannot measure the nutrient content, and be very careful to keep them down as far as you can and not disturb the area.
If you do, do a large water change asap.
Vacuum the gravel in that area.
I don't use these, They do not have inmpact on plant growth if the water column is supplied and there is no plant that needs(or does better) root ferts for macro nutrients I know of.
I can control and maintain the water column easily by dosing KNO3, traces and KH2PO4. Adding ferts to the substrate is not bad, it can be a good back up IMO, but only if you allow the water column to have too little will the plants start to use the root sources.
They need to come out with a NO3 only based fert stick.
Regards,
Tom Barr