Our group visited in December there were lots of school trips I would guess a middle of the week visit may be less traffic. Hope this helps

Per the Georgia Aquarium website: Happy birthday, Georgia residents! Georgia Aquarium wants to help you celebrate your special day with a very special offer. Visit Georgia Aquarium on your birthday, and your Aquarium admission is FREE! Simply click the Tickets Button here or at the top of the page, and select the number of Birthday Guests that will be visiting. Your will be asked to show proof of your birthday with a valid Georgia ID or a copy of a birth certificate for children to gain access to the aquarium and celebrate your birthday by having a whale of a good time at the world’s most magical aquarium, the Georgia Aquarium! (If you have recently moved to Georgia, alternative proof of residency can be a utility bill / statement with your address on it). *Ticket must be redeemed and used on the day of your birthday. No exceptions and no refunds for previously purchased tickets. Offer valid to Georgia residents only. Birthday offer can not be combined with any other offer. *Standard walk-up rate: $42.99 + tax

I download the app and did it that way.

Please contact the Aquarium directly.

No, we got right in with pre-purchased tickets

Sorry, we can not answer that for sure. Please see if any information is on their website.