Important questions about diy root tabs!!!!

Hey everyone!
I am planning on making DIY root tabs (the ones where you buy slow release plant fertilizers and put them in gelatin capsules).
I hear that you should use osmocote/osmocote plus. However, osmocote/osmocote plus have been discontinued. So, I did some research and learned about something called Miracle-Gro, slow release, all purpose plant food.
I was going to purchase this product, when I realized I had some old plant fertilizer. The fertilizer I have is Miracle-Gro Shake 'n Feed, slow release, all purpose plant food. I have 2 concerns about this product. First, in all the youtube videos, the fertilizer people use to put in their gelatin capsules is always brownish tan. My fertilizer is green/turquoise. Second, my fertilizer is old and has been sitting in a container for a while, so when I went to get it the fertilizer was soaked. I drained out 80% of the water and I thinly spread the fertilizer out on a piece of cardboard to dry.
This fertilizer is the same brand as the one I saw online, hyas the sameish nutrients, and it is slow release. It is just a completely different color and has been soaked.
If I dry this, will it be OK to use in my aquarium as a rot tab?
THANKS!!!!!
http://www.miraclegro.com/smg/goprod/miracle-gro-continuous-release-plant-food/prod70290 This is what I have except mine is in a bag.