Thankseish... seems nobody replied to @Zubair
1.The Idol evaporator cooler is a lot cheaper to run. Electricity consumption of a pump and a fan is a lot less than that of a chiller.
2.Although evaporation cooling is not that effective in humid environments like at the coast of Natal.
3.Your RO consumption will also be a lot higher, so you might need a bigger RO tank.
4.Chillers hot air outlet can also increase the room temperature, so it ends up fighting itself to cool down. Better if you can house the chiller away from the tank or even outside in a doghouse or something that will protect it from the environment but still allow for sufficient airflow.