Serious divers going to Cozumel look for serious
operators such as Aldora Divers and Living
Underwater (reviewed in the May Undercurrent), so
when our traveling feature writers find an exceptional
operator, we like to pass it on:
 Earlier this year I scheduled a one-week dive trip
  with Aquatic Sports Cozumel. Owner Sergio Sandoval
  has run his small family-owned business for more than
  30 years. He and his son, Sergio Jr., provide the underwater
  guide services.
 I was always on the largest of Sergio’s two boats,
  which had a covered deck area with enough seats for
  eight friendly people, thought there were never more
  than four. Other than the bunks in the cabin, there
  was little space to store large, housed cameras and he
  needs an adequate rinse tank. On the other hand,
  there was a marine head -- a luxury on Cozumel’s
  smaller boats. Tanks were filled to 3200 psi. Nitrox is
  available.
 The dives were always guided. Although we were
  advised to stay within sight of either Sergio or Sergio
  Jr., I was never hand-held. I was encouraged to dive
  my computer, but decompression dives were prohibited.
  Because boat traffic is very heavy, the Sergios
  always towed a tethered marker float. They asked me
  to signal when I had 500 psi remaining and make a
  safety stop under the float. After I surfaced, the boat,
  which had been following the float, would come pick
  me up. The first mate or captain was always there to
  carry my tank and assist in donning and doffing. They
  provided safety sausages for those who didn’t have
  their own.
 Each day, Sergio picked me up and dropped me off
  at my hotel (Iberostar). On the first day he loaded my
  gear aboard. From then on, he transported my gear
  back to his marina, rinsed it and hung it in his secure
  locker till the next day. I watched other hotel guests
  shlep their gear off their dive boat after every trip and
  haul it down the long pier to the dive shop for their
  own rinsing and storage.  
During my week we hit many highlights: Devil’s
  Throat, Palancar Gardens, La Francesa, Punta Sur,
  Columbia Reef, Central Pass, plus Santa Rosa and San
  Francisco walls. My two morning dives were separated
  by a one hour break for a light lunch and time for a
  siesta or stroll along a beautiful beach. The afternoon
  dive was several hours later, allowing time back at the
  hotel. Sergio also provided great night dives very
  close to his marina where there were no currents to
  worry about.
 Aquatic Sports Cozumel accepts Visa and
  MasterCard (Phone 011 52 987 2 0640 or email:
  scubacoz@scubacozumel.com). Sergio charges US$69
  for the two-tank morning trip and US$37 for a onetank
  afternoon dive. The Iberostar (www.iberostar.com) is close to most of the dive sites, but a half hour
  from downtown San Miguel by cab. The five-year-old
  all-inclusive hotel is beautiful, with two-story bungalows
  spread throughout manicured grounds. The food
  in its three restaurants is great! Reservations must be
  made by a travel agent or online booking service.