Maybe I'm splitting hairs but it's not about the cell-phosphate relationship. High phosphates will eat up your chlorine in the pool. If the phosphates are high enough the cell won't be able to keep up and it's time for phosphate removal, either with No-Phos or Alum. My phosphates build up >3000 ppm within 3 years from fill water and even with supplemental bleach, residual chlorine disappears quick at that value. Phosphates won't reduce the life of the cell unless you increase output to compensate for them.
Hope this helps, Tony