You do not need, and in fact cannot use, check valves for your filter. Check valves insure one-way flow. If you put one in the out-flow from the tank to the filter in such a way that it would prevent your tank from emptying, then you would also be preventing outflow to the filter.
If your filter isn't up to the task of handling the couple feet of head pressure, with or without power, you need a refund.
If you are adding other things inline, such as CO2, auto-top-off, or ferts, use a check valve on those lines.
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