Have a hayward de filter that is blowing de back to pool... just replaced grids.. found a few hairline cracks in manifold , have ordered another one , for now I sealed the cracks with epoxy,, it seems that when I set the grid assembly back onto the outlet pipe it doesn't seat snugly, replaced the o ring already, the de is being pulled from the tank somehow obviously and being sent back to pool via the return?. any thoughts out there as to what else I could look at as the problem

You have described several things that can cause earth to be blown into the pool. The grids can be difficult to seat and who know how perefcet your epoxy patch job is. Grease that O ring with plumbers grease to help it seat more easily.

have a hayward de filter that is blowing de back to pool....just replaced grids..found a few hairline cracks in manifold , have ordered another one , for now i sealed the cracks with epoxy,,,it seems that when i set the grid assembly back onto the outlet pipe it doesnt seat snugly, replaced the o ring already, the de is being pulled from the tank somehow obviously and being sent back to pool via the return????......any thoughts out there as to what else i could look at as the problem
Thanks... wanted to get through the weekend and then tear down and install new manifold , will be very careful inserting the grids and hopefully this problem is history

I have had two Haywards. The first one thr original grid were still fine after 20 years. The second failed after 3 seasons, go figure.