I am new to this forum and I look forward to getting to know some of you.

We have a 12 x 16 feet pool in Merida and experiencing some serious water loss, I am not sure how much of it should be attributed to normal water evaporation?

Hi and welcome!
It will depend on the surface area of the pool, the temperature, and the relative humidity and the wind. Generally, you can expect about 1%-3% of typical pool volumes per week. In my pool I am loosing somewhere around ½ inches daily in the summer and less than that in the winter. If you are losing more than an inch a day, you may have your pool checked for leaks.

OK, it appears that we have a leak, what do we do about fixing it? Is there someone in Merida who fixes leaking pools?

In most cases fixing it is less problematic than finding it. There are people who find leaks professionally in Merida, I don’t have their numbers but if you go to “Hydrotrol” pool supply located in the back of “Gran Plaza Mall” they will give you this guy’s number there. He will find a leak and your plumber will be happy to fix it for you.