I have a korallin 1502..reactor I ordered a new solenoid cause I noticed it doesn't shut down when deenergized . Tthe other day my reactors ph went too low and turned. Part of my media to mush(the media is only 2 months old usually lasts 6 months) Over the past few years as my media gets low I just dump it and add new media but after some thinking doesn't it wiser to rinse the old media reuse what is good and top off with new media? That's what I did yesterday I know the manufacture recomends replacing media completely but thay make money by selling more media all it is is coral skeletons so I don't see why we should discard the portion that is still good I use arm coarse media