Hello,

I'm living in Mexico and recently had a 3x6x1.5m (7100 gallon) pool built - it has 1 skimmer, 1 return drain, a bronze drain that looks like a bathtub plug and 4 returns. There is one pump for the filter and another that fills (and drains?) the pool from/to an underground well

The builder briefly went over the plumbing but there was a bit of a language barrier and I don't fully understand what the valves do or what position they should be in while doing maintenance.

Here are some pictures of the plumbing setup and filter:

https://imgur.com/a/J5nmzhd

From left to right the pipes are: Drain, Skimmer, Aspi, Return, and the pump to fill (and drain?)

[edit] I think the "aspi" means aspirate or drain. Hard to tell from the picture but the "aspi" connects with valves to the return, the pump to fill, and another pipe that goes into the ground.

In the current position the skimmer works fine. What do I need to do to drain the pool or backflush the filter?

Lastly, how long a day should I run the filter pump?

Thanks in advance for any input/suggestions