This is absolutely my fault and no harm was done to the fish or plants in my tank. For at least a day possibly two neiher of my filters were filtering. It is a heavily planted tank housing gbr's and apistos so when I did the last filter maintenance I added a sponge pre filter to both intakes. I am using an Eheim 2213 and an Ecco 2232. As soon as I removed the sponge prefilter the output shot right back up. Is it common for the prefilters to stop the flow completely?