I would like to show you how to make an oxygen tank for the fish that I am using and quite effectively without electricity. The principle of operation is an oxygen cylinder and the usage time is from 30 minutes to 3 hours depending on You can adjust the gas output more or less You can use a larger bottle to effervescent longer One thing to note is that after you're done, you should test it to see if it's released by soaking it in. water to achieve optimal effect Any questions and contributions you can leave below the video I will answer. Thank you for watching the video.