Day 21 humidity problem

[Meh245]

This is my first time incubating eggs. I am using an older little giant 10300. On day 18 I filled the reservoirs,added a saturated sponge, and was able to obtain 70% humidity. It is now day 21, one chick has hatched and one is pipping; however, the sponge is now dried out, the reservoirs are very low and the humidity has dropped to about 50%. I do not know if I should risk opening the lid to add more water, or let the situation stay as is. I tried to add more water through the ventilation whole at the top, but I am not obtaining the spike in humidity that I am looking for. Any advice is greatly appreciated!

 

[spotsplus]

Before they really get going with the hatching I'd open up and rewet the sponge and fill the reservoirs as the humidity is going to go even lower as they start to pip and zip.