Kiddy pool?!? That must be hard to hide! Advanced Nutrients Heavy Harvest is the best IMO. You mix it in when you plant outdoors. They have a spring, summer, and fall mix. Time release stuff. Mix in the spring stuff and go back and add the summer later. The benifits are that you won't have animals digging up your plants to get the bone meal or blood meal. The stuff is really affordable and is in granular form. Check it out!