Regrettably just did some diving with Aqua Scuba and I think you will find far better shops out there. While they are the cheapest shop on the island, I found them quite unprofessional and unsafe. Their gear did not seam to be well maintained and when other divers had issues with tanks and regulators, they just replaced them, while not tagging out the other equipment problems.
They also deemed it safe when they took a 10 year old diver down to 60 ft when their depth limit is 40ft. I wasn't the least bit impressed or felt comfortable knowing that they would do this with a child. I've seen alot of adults dive outside of the recommended depth limits as per their training, but I wouldn't be pushing children.
I also found that their guides gave the guest very direct suggestions towards tipping them, through stories about not making enough money, supporting their families, specifically how much their rent was. I've been working in the dive industry for 6 years on and off in various countries with different standards of living, and while I made peanuts compared to what they say they are making, I have never found it professional in ANY way to talk to guest about how little I made so that they could feel sorry for me and give me tips.
Gaz and Peter make very good suggestions. I would take their recommendations.