Dear D.,
The door stopper is good, but the time will come that if your child wants in the pool badly enough, he will stack tables and stools to get to it! About the same age that he will try to climb the fence!!
Put in a 4 or 5 foot fence of slats or iron work that has no horizontal toe holds. Also install some kind of bell on the doors. This can be as simple as the old fashioned shop-keepers bell or part of your security system. Ours dings every time an outside door is opened.
Find a pool company or a fence company that can recommend safety features.
D., please don't delay. Several children had alreay drowned in area pools this year!! There is absolutely no excuse for this!
And of course the most important safety tip is to WATCH THEM! Never trust anyone else to watch your children around the pool. Never go in the house to answer the phone or take the roast out of the oven if your children are in the pool area. Have a remote phone. I'm sure you will get more ideas. Use them all. the little things count.
Try a schedule with your 3 year old. Show him how the hands move around to show the time. Tell him you will get in the pool with him every day when the hands are at a certain place. If he trys to go out earlier he doesn't get to go that day or has to do time out. Whatever works for him.
Don't let friends and neighbors bring their children over except by invitation, preferably at our childs scheduled time.
This is very long, but every time I hear about another young life being snuffed out because a moment of inattention, I mentally add to my list.
God bless you. Enjoy your pool and your babies!
Grandma D.