Mosquitos

Hello,

We have an apartment in Mar de Pulpi. The balcony has plants with an irrigation system but the water is staying in the trough. This is, of course, a  breeding ground for mosquitos. Can someone please advise us wether this excess water should be draining away please. They are around even in the morning, haveing been bitten a few times already! Short of removing the planters completely is there anything we can do. Maybe a product which can be added to the water to kill the larvae? Any advice will be warmly welcome, thank you! Dawn