I've had a great deal of success synthesizing Copper Sulfate from Magnesium Sulfate by electrochemical means in this way: I fill a pint-size mason jar half way with a saturated solution of magnesium sulfate. I place a cork screwed copper anode into the jar with electrical tape covering the part of the electrode that comes in contact with the top half of the cell. I then place a small fluted coffee filter into the jar and clamp it to the mouth of the vessel to keep it suspended on the top half of the jar and fill the jar the rest of the way up. It's important that the bottom of the filter and the top of the copper anode have enough separation that Copper hydroxide/oxide doesn't begin to form where the two "half cells" meet. Using a ring stand with a clamp, i suspend a graphite cathode into the top half of the cell, taking care that this electrode doesn't touch the bottom of the filter paper. With a 5V/1A power supply, i run the cell until the bottom-most-layer (about 4 hours)has turned dark blue(3 layers will eventually form: inside the filter paper on the top half will be opaque MgOH, the bottom will have the Copper Sulfate and there will be a thin band of transition layer above this and below the filter paper). Next i siphon the bottom layer out into a flask and reduce it's volume over heat by half. after this cools to room temp, the remaining MgSO4 will cystallize and an even blue-e-er solution will remain. this is concentrated CuSO4 which i then also cystallize. Notes: There are two important reasons for using a saturated MgSO4 solution; the reaction in more interesting because precedes muuuuuuch faster than using a dilute solution so you see a colour change after about 15 minutes as opposed to several hours and having to run the apparatus for a full day before any significant amount of CuSO4 is detected, and since MgSO4 has a much higher solubility close to boiling than at room temperature, when you reduce it's volume by half over heat after you separate it from the cell it will easily crystallize when the solution cools to room temperature and it's solubility significantly drops. So after siphoning the CuSO4 solution from the cell, take care to filter it before the reduction, and again after the reduction using a hot filtration method. If you are unfamiliar with crystallization techniques, take the time to research it's main concepts on YouTube or through search engines. When the cell is running and you are collecting your "blue gold" the cell should be at a relatively cool temperature. heat is the enemy of this reaction and will make the whole system unstable, but the friend of it's separation into purer form. I have not tried running the cell in an ice bath, but i have tried running it around 110F (which was a disaster). Thanks to everyone else for their posts, which helped me develop this method over time. Let me know what you think, or tell me if I am doing something stupid.
