Como regular el calor en el armario

and exhaust fan will help reduce any difference between ambient temperature and cabinet temperature, but if not enough you need an air conditioner. intake air from a cooler area possibly? not really familiar with hid but 50-70cm is probably right. Can simply observe plant's reaction and adjust... will be similar to whatever you learn in future with minor adjustments needed. Generally, i'd pick height based on coverage. What results in good amount of light spread across the canopy? if well-matched to area of coverage should be the right height for plants too.