Suitable outdoor lighting is more decent and the reflection of light on the water creates a much more romantic appearance. Therefore, it is the most suitable way of lighting and allows the lighting to stay on all night, if necessary.
Generally speaking, underwater lighting always looks more artificial. Nature does not know night lighting and living beings in the water need a dark environment for much of the night. Therefore, it is necessary to turn off the lights after midnight, in the safest way with a clock switch. This way, the biological pool ecosystem can rest for a few hours. Just to confirm, colored lighting does not fit in any way.
Night lighting could have advantages, especially in tourist sites. The biological pool offers a fantastic setting and becomes an attraction even outside opening hours. Lighting can be seen as an advantage in terms of security. On the other hand, due to the lighting, the biological pool can become more inviting for nighttime bathing and this can be a problem, because biological pools are generally not monitored at night.
A biological pool is a bio-based solution, a slice of nature. Any lighting should highlight this virtue of landscape integration, not create an artificial environment.