The combined effect of nutrients and temperature was similarly tested by four-way ANOVA, with treatments (nutrient and temperature) as fixed effects, tank as a random factor nested in the nutrient treatment, and coral colony as a random factor nested in each tank. The tank effect was dropped from the ANOVA analyses because it was not significant for all the measured parameters. The factor of coral colony was significant for the algal density and Chl a again and thus, the combined effect of nutrients and temperature was tested by two-way ANOVA for each coral colony.