There needs to be a small amount of slack in the chain, but not much. As long as it is not holding the flapper up, it should be okay. Note that as the rubber ages, the flat part that makes the seal will start to collapes, and the dome part will sink. If the chain is too tight, it will then start to leak. The tank is designed so that you get the proper 1.6g flush if you just press and release. If you hold the handle down, you'll get probably close to double that volume, and should not be necessary. toto is a true large international company, so parts come from all over. that should nto be a problem.