Swapped Flex hose with PVC pipe

[Irishman]

So I just recently switched out my overflow hose with PVC pipe. It is creating a lot more bubbles in my sump then my flex hose did. Is this because that the water is filling up the whole area inside the PVC and it didn't in the flex hose? Would drilling a small hole in the top 90 degree PVC, highlighted in the picture, create more of a smooth flow to where I don't get a lot of bubbles shooting into my sump? View attachment 24819 View attachment 24820 View attachment 24819 View attachment 24820

 

[JuanGutz]

What about at the 90 out of the tanks over flow? That's where I always see holes. Or is it drilled at the bottom?

 

[Irishman]

I have not drilled any holes in the PVC yet. The highlighted are in the plumbing picture where the 90 degree elbow is where I would like to drill the hole. Just asking if I drill the hole will it create a smooth flow down to my sump and not create a high pressure flow going into my sump like it is now.