I diluted it 10 times by putting 100ml of CLIMA and 900ml of tap water in a 2L container.

When 1L is added, the diameter of the liquid surface that is in contact with the air is about 11 cm.

The pH of CLIMA diluted 10 times is 12.88.

pH after 8 hours is 12.83

The drop was only 0.05, so it depends on the shape of the container, but it's okay to leave it without a lid.