If you want to extend the ‘formal science’ out a bit, you could always cut back to just 2 days a week and then do read some living books on the third day.
I’m actually amazed that you do science three times a week. We have trouble fitting in one nature study ‘wild day’ and one family science day (working through Outdoor Secrets right now) and one chapter from the Burgess Animal book with my year 1 student. Over the winter the nature days have become fewer, so we aren’t even doing that every week right now. Three science days on top of nature study would just overwhelm me! Of course, my kids are young (6,4, 3, and 2) so maybe it will be different later.
Anyway, if you don’t want to buy anything new, there are some fun living science and nature books on mainlesson.com that you could read online to supplement your Apologia, or replace it once it’s done. I’ve been previewing them to see what we want to read after the Burgess Bird, Animal and Seashore books.
Joanne