I have successfully blown out the 6 returns in the sides of my pool walls and my two skimmers. I also have 3 floor returns (pop-up from the floor) and a main drain. With the the first two floor pop-up returns, I saw a few bubbles come up when I blew out those lines; however, with the 3rd and subsequently deeper pop-up, I saw maybe two bubbles and with the main drain, about 10 ft. deep, I never saw any.
My question - Did I not see any bubbles come from my main drain because the main drain is so deep that my wet-dry vac blower wasn't strong enough to blow out that line? So I may need to have someone come out to just blow out that line for me?
Thanks in advance for any help with this question.