Blowing out lines

[Poolclueless]

I have two main drain pop ups on the floor of my pool. When attemping to blow these lines out I was able to only get one of the drains to bubble. I am unable to get the second one to blow. I'm wondering why this is and should both of them be blowing bubbles? If the other won't blow will this be a problem. My pool is only 6 feet deep where the two pop ups are.

[1idejim]

I have two main drain pop ups on the floor of my pool. When attemping to blow these lines out I was able to only get one of the drains to bubble. I am unable to get the second one to blow. I'm wondering why this is and should both of them be blowing bubbles? If the other won't blow will this be a problem. My pool is only 6 feet deep where the two pop ups are.

You could be experiencing one or more issues that are preventing the air from being purged from both drains.

I have to assume that you have VGB compliant drains. If that is the case, the suction line could have been plumbed
1) in series (or) straight in line with the drains
2)the drains are of unequal height
3)one drain is closer than the other if plumbed with a center tee
4)you don't have enough air volume

Any combination of the above could create a situation where air bubbles won't escape equally.
I would suggest that you either turn the pump on and dye test both drains to prove they're working or increase the volume of your air source.

Many times a vgb drain will suck great but not purge very well.