I am going to be going on vacation for a little over 7 days. No one will be around to check on my pool. I have a 20,000 gallon pool and have been taking been successfully taking care of myself with TFP methods for a few months. I need to try to keep things going while I am away. I think I will put the tricholor tabs in a floater. How many would I need? Will it last? My CYA will be around 40 at the time.