I have 4 clivia plants which are in the shade on my balcony In Ras Al Khaimah, United Arab Emirates.

The plants have been here for 7 months and during the winter I watered them 600ml every 7 days. It is now considerably hotter, and Inwas doing 600 ml every 5 days. The tips are starting to turn brown, and I am not sure if it is over or under water?

Soil is reasonably sandy and after 5 days nearly completely dry.