> I want to start using the homemade recipe, but I don't want to overdue it. Any advice?<
Yes, read the original thread about the supplement.
I'll repost the important part for you:
>Adding this at the rate of about 10 ml/gallon of tank volume (in a stream of water where it will get mixed into the tank quickly) will increase the magnesium level in your tank by about 100 ppm. It's never a good idea to make changes too fast to a tank's water chemistry, so if your tank is low in magnesium by more than 100 ppm I'd still only add 10ml/gallon/day until you are back around 1250-1350 ppm. So, for instance, if your 100 gallon tank were 300 ppm low in magnesium, you'd need about 3 liters, or almost 1 gallon of this solution to get back into the proper range on magnesium.<