Clear-It is without question, the strongest most effective RV black tank unclogger on the market, and your best option if you have any kind of clog, back-up, or blockage in your black tank! Clear-It’s boosted blend of fast-acting enzymes and extra-strength bacteria works quickly to break through and digest the waste that is causing your RV’s black tank to back up and is effective at removing pyramid plugs, blocked plumbing lines and compacted waste that has hardened inside your black tank.