The rate of dissolving is very critical here, Osmocoat is pretty slow.
So not much with the NH4.
It's more longer term stuff.
For faster: soil work pretty well, but then you have the NH4 issue, same with Jobes sticks.
But if you boil(10min)/mineralize(shallow water soaked for 3weeks)/bake(1 hour at 400F) you can remove it from soils.
So a mix of both is workable.
If you look in ADA powersand, they add a similar product as well.
BTW, many things in sediments we use float, peat etc, we just bury it with sand on the bottom.
You are not using much, the rate is slow and so we'd expect little added growth from it as well, but it's benefit is the longer term time frames.
That's the trade off.
Ideally when designing and thinking about nutrient sources, you will want to mitigate things by adding the benefits of one thing to balance the trades offs you do not like.
This is the most logical approach.
To get the most out of any nutrient source, we should look to the water column, the long and short term bioavailability in the sediments.
Adding Water Column nutrients will reduce the draw from the sediment sources and allow it to last longer.
Adding nutrients to the sediments will allow you not to depend on the water column as much and you can mess up more or use less(using "more" will not hurt however), forget to dose as we do at some point.
Basically allowing us more back up and using several methods synergistically together.
Same for short and long term supplies of nutrients in the sediments.
Some have suggested plants prefer sediment sources, however, aquatic plants are opportunistic, they take nutrients where ever they are available.