There was a thread asking a similar question recently and since the site is Reef2Reef folks opined that you can over-filter a reef by stripping the water so clean of nutrients (including micro fauna) that the coral would starve which can be a real problem in a reef tank.
In a fish tank you could argue that over-filtering is not a problem because the ultra clean water is not going to harm the fish like it does coral.
I knew a guy who set up a fish tank that had a 3000 gph pool pump on it with the idea that the strong current would prevent detritus from accumulating in the tank and sweep all the waste products into the sump where the filter socks and skimmer would remove all the waste and he would never have to vacuum the bottom of the tank to keep it clean. He didn’t have any heat filters (a chiller) to remove all the heat that the pump generated and the tank was always running too hot for the fish to live in and that is one way of over filtering a tank.
With modern dc pumps that produce low heat he might have gotten away with it? Still, if the currents in the tank are pulling the fish out of the tank and into the overflow I think that could qualify as over filtering a tank.
I once set up a 125 gallon tank with lots of filtration and power heads to keep the water flowing torrentially to see if I could keep the detritus from collecting in the gravel. I put a blue tank in the tank and it swam as fast as it could but in a few days I found it had died trying to stay in place. That’s how you can swim a fish to death and I think by default the tank had too much current for a fish tank.
If you can’t keep the coral sand on the bottom of the tank I think you have too much current and you may have over filtered the tank as well.
Hth.
