Yes, you can use what you have left over - I only use them when I have to shock my pool, and it is ok to put them in the skimmer on occasion. I wouldn't do it all the time, but if you deal with staining it is a good idea because the water that goes over the puck in the skimmer goes into the filter before it goes back in the pool, therefore if the metals are ready to fall out of solution they will land on the sand in the filter instead of the pool surface. It is part of some instructions that Pool Doc gave me when trying to get the metals "out" of the water. Keep us informed on your progress, it is how we all learn!

Thanks for the kind words Waterbear! It's great that it's pool time again here in the northeast! Well almost It's great to hear from everyone again!