BBA building up suggests you don't have enough CO2 dissolved in the water. If you make or buy a drop checker, use it with 4dKH distilled water in it, you can be sure you have enough CO2. GSA tends to show you don't have enough phosphates in the water, so increasing the phosphate dosing by about 50% should help that. I don't think there is any chance that aging bulbs are your problem.