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Wet drys are just fine. They can cause nitrate to climb if the tank is over-stocked and over fed. The sure-fire way to know if your wet/dry is working okay is to turn to your water parameters. If your water is good, your filtration is just fine. It is a good idea to remove the bioballs and replace them with LR
rubble over time, it is a far better biofiltration media then the bioballs. I have a pic of my wet/dry in my gallery with LR
rubble in it if you care to look. Good luck...Lando