Anthony Apollo 52-2 filter problems

[jj401]

I bought a house that has a pool with an anthony apollo 52-2 filter. I am getting DE in the pool, before we closed on the house the grids were replaced. When I cleaned the grids there were no holes. How do I get the grids out and check the pipes for cracks. Thats the only other place I could see that the DE would be coming from. Any other IDEAS.