It shouldn't cause algae, at least I've never heard of Equilibrium causing algae. For GH levels, it really depends who you ask. In general most will agree that anything over 3 and below 10 is good. Don't worry about GH/KH ratios. Maybe try raising your GH to 5 or 7.
Keep in mind that Equilibrium will also add potassium, iron, and manganese. If you don't want those extras, look for a GH booster that only add calcium and magnesium.
There's an online calculator that's very helpful. Just google "rotala butterfly calculator". Using this, you can calculate the amount of dosing required to bring up your GH by selecting the product and how many degrees you want to increase GH by. It will also tell you how much iron, potassium, calcium, etc will be added to your water if you're using Equilibrium for example.