Just FYI (since you've already drained your pool), you could probably use the "sheet" method for draining and refilling the pool without actually changing the amount of water that is in it and have no risk of cracking or popping out. The sheet method is described elsewhere in this forum but essentially you drain water from under the plastic sheet while filling in new water from the top. You can also use large bags instead, though your pool will look like a scene from Cocoon. You can also use a silage tube. See later pages in this thread for a humorous discussion about these methods.

Another alternative, that takes more water, is to drain from one side of the pool while refilling from the other. This will never completely replace all the water in the pool, but you can perhaps get enough dilution to remove enough of whatever is in your pool that you want removed. This would normally be more for diluting the amount of CYA in your water -- it's not a good method if you want to do significant dilution much beyond 50%.

Richard