hello, everyone finally has a clue!! thank you all, it could actually be black algae or sand, this story of the strainer in the sand filter, I had never thought about it and seeing the result of the second sample, yes it seems to be sand? https://zupimages.net/up/23/40/lg2n.jpg

Hello,

no actually, I changed the content of the sand filter at the beginning of the year because I had that last year too
There is no net in the sand filter? there never was one.
when loading the coarse and fine sand, I respected what was in the capacity, filter approximately 3/4 full

Hi everyone, every day I clean the bottom of the pool (7x4) to find the same amount of "dust" at the bottom the next day! I have the impression that the sand filter does not stop this "dust. I completely changed the sand (13 m.cubes) coarse and fine, the same! I don't know...

thank you izentrop, it will be useful, I print it.

I forgot, behind the house attached to the house there was a sawmill for handyman I think that was why he had three-phase
this sawmill cabin has been closed for a while and no more engines.

thanks for the link, but it's just an ad for the Consuel.

thank you for your comments, I forgot to mention that there is a three-phase pool pump and a three-phase well motor, so I guess that's why the previous owner had three-phase. find the neutrals with a colleague we started, then put everything back as it was, it took a...

hello to all with a colleague we decided to put back in safety (safety is the name) of (an old distribution board with fuse holders. house of the 70s has common neutrals!! I read here that someone one had "tried" but didn't seem to do it?. we're in tripha...

Hello everyone, I have a closed fireplace (insert) I wanted to recover the hot air in the hood, but I really do not see how? the living room ceiling (where the fireplace is) is a cathedral ceiling, so no roofing, can you do that with exposed ducts? going down ...

hi to all my pool is a 7x3 shell all around, there is a 15cm concrete slab, but between the edges of the pool and the slab, all around there is a space of about 3 cm, the pool has ten years, and weeds grow between the pool and the concrete slab, I don't know ...

Hey ... not stupid this idea? ... aesthetic side it will be much more beautiful than the paneling!
Insulation side that should not "worsen" the situation, I think? ...