air bubbles from return after blowing lines and plugging

[Sumthinred]

Hello,

I closed my pool myself for the first time this year. Everything seemed to go smooth. I used an air compressor to blow out the lines. I have three returns, all on the floor of the pool, one in the shallow end, one in the middle, one toward the deep end. I blew them all out closing the valves as i went to make sure they were each clear of water. when done, i put a rubber plug in the end near the filter. shortly after, i noticed bubbles coming from the return in the shallow end. how is that possible, I am worried i have a cracked pipe now, not sure if that even makes sense. the the valves are closed, and the line is plugged, how could the air get out? the returns themselves are not plugged as they are on the floor of the pool. is this normal?

thank you,

 

[Texas Splash]

Have the bubbles stopped? Is the pool's water level dropping? If not, perhaps it was some residual air that got in the line when you were closing everything up at the pad?

 

[Sumthinred]

Have the bubbles stopped? Is the pool's water level dropping? If not, perhaps it was some residual air that got in the line when you were closing everything up at the pad?

I checked the water level this morning, didn't move, I will check again in a few days. Cover is on now, so I am not sure if they stopped. I am hoping it was just bc I used an air compressor and the lines weren't completely clear of water and some air was trapped. I still have plenty of time before any chance of freezing around here, I may invest in a better line blower and blow them out again....