Appropriate water exchange can maintain optimal physicochemical water parameter conditions, remove harmful metabolites, and provide the necessary nutrients for the growth of Caulerpa lentillifera. This research aims to analyze the effect of water exchange intervals on the growth of Caulerpa lentillifera and determine the optimal water exchange interval for the growth of Caulerpa lentillifera. This research was conducted for 45 days, with maintenance activities carried out at the Production and Reproduction Laboratory, Faculty of Agriculture, University of Mataram. This research was conducted using a Completely Randomized Design (CRD) method. The method used in this research was experimental, employing 4 treatments and 3 replications with A (daily water exchange), B (water exchange every 5 days), C (water exchange every 10 days), and D (water exchange every 15 days). The seedlings used in this research were collected from the waters of Batu Layar, Senggigi, West Lombok. The seaweed required for this research totaled 120 g, with a distribution of 3 g per research container. This research utilized 12 glass jar units, each filled with 1 liter of seawater. This research also involved the addition of nutrients to support optimal growth of Caulerpa lentillifera. The culture medium was enriched with the addition of nitrogen (N) 30 ppm, phosphorus (P) 4 ppm, and potassium (K) 6 ppm. Based on the results of the Least Significant Difference (LSD) test, different water exchange intervals showed a significant effect (p<0.05) on the absolute growth of Caulerpa lentillifera, Absolute growth is the increase in weight and length of organisms during the maintenance period. Statistical analysis showed that water exchange intervals had a significant effect (p < 0.05) on the relative growth of Caulerpa lentillifera, Relative growth is the percentage increase in organism weight during the maintenance or cultivation period. Based on the results of the Least Significant Difference test, water exchange intervals showed a significant effect (p<0.05) on the specific growth rate of Caulerpa lentillifera, Specific growth rate (SGR) is the percentage of daily growth calculated based on seaweed weight measurements every week during the research period. Statistical analysis showed that water exchange intervals showed a significant effect (p<0.05) on the biomass residue of Caulerpa lentillifera, Biomass residue is the remaining biomass that survives after a decrease in biomass amount following growth. In conclusion, the water exchange interval of treatment C (water exchange every 10 days) showed the best performance in almost all measured growth parameters, with a relative growth value of 13.42%, daily specific growth rate of 0.630% per day, biomass residue of 58.68%, and absolute growth of 504.0 mg. Further research is needed on water exchange percentage parameters and nutrient optimization, including both micronutrients and macronutrients, as well as water quality factors such as physical, chemical, and biological parameters.
A et al. (Wed,) studied this question.