Copper gluconate mixes easily with warm sugar syrup or HFCS. It will give your syrup a slight tinge of blue.
For best results, a colony needs a total of 12.5 grams of copper gluconate per year, mixed at a ratio of no more than 2 grams per liter. There is no fear of toxicity to the bees, according to the chemists at Jost Chemical (www.jostchemical.com) but anymore than 2 grams per liter becomes unpalatable to the bees and they have a greater reluctance to accept the feed.
In plain English, you will want to feed a total of 2 tablespoons of copper gluconate per hive, over the course of one year, ideally half in the spring and half in the fall (before supers are put on and after they are taken off), but you could feed all of it in the fall or in any seasonal combination, as long as the supers are not on to collect honey for extraction.
To mix copper gluconate, place 1/4 tablespoon in a quart jar and add warm syrup (either 1:1 or 2:1) and stir. Or mix 1 tablespoon per gallon, and feed a total of 2 gallons to each hive over the course of a year to give you a total of 2 tablespoons of copper gluconate per hive.
If you want to feed a larger quantity, mix 1 cup into 16 gallons of syrup and dispense the syrup to your hives. It makes no difference if you feed sucrose (sugar syrup) in ratios of 1:1 or 2:1, or if you blend other ratios of High Fructose Corn Syrup (HFCS).
Obviously, this is to be fed when the honey supers are not on the hives, both in the spring and in the fall.
NOTE: It has been my experience that some bees will balk at taking the syrup with these levels of copper gluconate. If your bees are finicky and fussy, try these three suggetions:
1) add more untreated/plain syrup to what the bees have refused to eat. This will dilute the copper gluconate. Then when you mix additional batches of syrup, cut the dosage of copper gluconate by half. 2) feed a "heavy" syrup, or 2:1 to make the syrup more appealing to the bees, and be sure and feed when there is a dearth of nectar (bees will always prefer nectar to syrup). 3) add recommended dosages of Honey-B-Healthy to the mix to increase the palatability.
Or do all three suggestions. The bees will take syrup with copper gluconate, but sometimes they have to induced to take it.