David Rose - outdoor sporty swimming (Brussels)

Hi, I am looking for someone who is a member in David Lloyd Sports club. I would like to use the swimming pool there as that is the only outdoor pool in Brussels, however I would not like to become a member for this reason as this would be max two three times a month and their subscription is pricy. However there is a possibility to get in if i go along with a member for 35 euros, which is still pricy but I would pay it. Is there anyone here who is a member and would be okay to bring me alobng?
Many thanks for the response in advance!
p.s. does anyone know any open air swimming pool in Brussels for sporty swimming?