So..I've been building a 10 gal vert for about a week. Everything was done and I was going to plant today...I'm getting some bastis tomorrow and wanted to put them in this tank. ( I know I should have had this done months ago

I go to start planting and notice my GS has shrunken a lot! I've already done filler applications twice from very minimal shrinkage....now this? I'm scared to fill more if this is going to keep happening. Should I fill it again and hope thats not the case? I don't know what to do because time is of the essence and I'm picking up the frogs tomorrow.