I think the problem is also with the ehim pump will not hold the water when the power is off.
Christy are you on Zeo?
You can also just dial down the flow though the rock to about 1/3 after the 2 week rock break in time increase it to 1/2 flow.
Then at about the 3 rock change over you can increase the flow to the full 300gph.
I found about 200gph works best
J
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