I just got some Osmocote flower and vegtable 14-14-14 it was a 1.25 # bottle for 7.99, 500 00 gel caps on ebay for 9.99 now I have 5 years of root tabs. Miracle Grow Shake and Feed is made by the same company Scotts it's 10-10-10 and a slow release fertilizer that lasts up to 3 months Osmocote claims 4 months. The Osmocote is a polymer coated slow release fertilizer that releases slowly and takes a week to swell and release ferts, the Shake & Feed my be the same thing but they didn't have a Data Sheet at Scotts for that product, so unless you find someone that claims to have used it with good results, I would wait to find the Osmocote. Get on the phone and try the local hardware, home depot, and lowes, btw I got the smallest bottle and have a third of a bottle left after filling 500 00 gel caps. Also some people get the soil and make mud sicles to use in their tanks, good luck.
It may be harder to find in Hi or did you mean high??? that makes it even harder. No need to fear we won't come to Hi and start asking around for Milesm and if we do someone is bound to call the cops.
I found some Osmotocte Plus in 2 stores locally. By all the dust on the bottles, these have been on the shelves awhile. Doesn't look like any new stock will be available from the parent company Scott. They own both product lines and it appears they are consolidating between Osmocote and Miracle Grow somewhat. Luckily that 4.5 lb container will last me many years if not past my lifetime.
The 1.25 pound container of Osmocote fruit & vegtable 14-14-14 made 500 00 sized gel caps and there was a third of the bottle remaining, I put 32 or 36 caps in the substrate of my 150 gallon and figure I have a 5 year supply not including what remained, so you should have 2,700 00 gel caps in your bottle and that would last me 27 years, it's a really good deal on substrate fert.
I used the Miracle Gro that you are supposed to mix with water and then water your vegetables. I just mixed some of it into my compost substrate, still dry, and my fish have been fine. My plants are growing really well also. As far as shaking it into the water column, I dont know. I think I would rather mix a solution of this up with water and dump it in there. That way you don't have to worry about your fish getting ahold of a chunk and dying from eating it.