Most plomeros can retrofit your plunge pool for filtration. They also know all about your yucatecan water system to look at whatever problem you're having. I'm out in San Crisanto, so anyone here wouldn't go there. But ask around at the local hardware store for a plomero and then ask about whatever your problem is.
If you don't have Spanish, "Conocse un plomero bueno? " is 'do you know a good plumber?' and "Tienes su datos, por favor" is 'Do you have his information, please?"
If possible, contact him through WhatsApp, the messaging app. Everyone uses it and it lets you run your questions through a translator before sending and after receiving, so you get good communication.
If you have Spanish, sorry for the assumption. And a hardware in Chelem should have English-speaking folks around anyway.