"empty your tank on your floor..."
Who are all those people who have successfully ran filtration systems below the tanks waterline for years, without any problem and without being perfect all the time.
Some have run the same canister for 15-20 years without so much as a drip.
Same can be said for sump based systems.
If there would be a problem, one would have to look to the operator first, then the equipment.
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Will agree, 100% with keeping your first tanks filter system simple and easy to maintain.