I was in Nicaragua last year (pre-IC) and remember having to buy bottled water no matter what. I'm not sure as far as "brands" go, but I'm assuming you can't be too picky as most people there don't even have access to clean water! Hopefully you've healed to the point where this won't impact you too much- I'm guessing you'll be totally fine with any of the bottled stuff. Some more expensive hotels and restaurants may have safe water but always ask. I was also in Costa Rica and and would just get a huge jug at the store (you put down a deposit that you get back when you return it), keep it my room, and fill up a water bottle as needed. I found this was a great method and you don't have to waste a million tiny plastic bottles. Hope this helps in some way! Nicaragua changed my life, hope you enjoy it!