Preliminary study on improvement of pond water quality by bottom aeration

We conducted an experiment on Litopenaeus vannamei and Portunus trituberculatus aquaculture pond during Aug.~Oct. 2008 to study the improvement effects of bottom aeration on the water quality. Results show that 2~3 h bottom aeration can decrease or eliminate stratification of dissolved oxygen (DO) and increase DO content significantly (P＜0.05).The best time for operating oxygen-enriching machine is 8:00~11:00 am. Concentrations of ammonia nitrogen and nitrite in the experimental ponds are 72.5%~74.1% and 2.6%~2.7% ofthat in the control,respectively. Thus, bottom aeration can facilitate oxidization in the pond, decrease content of harmful substance and improve pond water quality.