Thanks Sylvain, must have been an immense work!
If it is of any use to you, I have backups of some threads that I was particularly interested in that contain more recent posts, including pictures.

Threads including...
pigmented hybrids from italy
Citrus hybrids I never heard of

and the threads of my own collection.

I'd say that it should at least be available to those of us who have contributed to it!

Those are some beautiful fruits!

They should put the server owner in jail!

I tasted ortanique for the first time past winter season. It's like a mandarin with the size of an orange and has a great taste! I love it!

Thanks again for the info!

Thanks Millet. Apparently small details can make a difference.
Is Tween-20 some kind of soap? Would it be possible to obtain the same effect by adding some soap to the fertilizer solution without damaging the plant?

Thanks for the reply. I do have a good liquid fertilizer for citrus with about the right NPK ratio but I'm still having issues with deficiencies, probably caused by the pH value of our tap water which is actually way too high (average 7.9 according to the data of the tap water company). This probably causes iron deficiencies. This liquid fertilizer can also be used for foliar application. Maybe I should do that! Never tried that before...

It's a good thing we don't have fire ants here! 

This is the product I used:

I could give that a try again then, and maybe let the water flow in slowly via the bottom of the container so the air inside the soil has the time to evacuate...

I'm lucky then, the ants that live in the yards here are not agressive at all . I just don't want to take them inside during the winter. If they're not gone by then the tree will have to stay outside and I'm pretty sure it will not survive...

I have a little problem with one of my citrus plants... the container it is growing in appears to be the home for an ants nest. I don't think the ants are a problem for the tree. They do cultivate some aphids when they are "in season" but other than that I think they leave the tree alone. The issue is that I have to take the tree inside during the winter season and I don't want to take the ants nest inside with it.
The ants nest was probably already there during last winter as I occasionally found an ant running around on the floor. I just didn't realize where it came from.
So I want to get rid of the nest. I already replaced the soil as much as possible last spring but that apparently didn't stop them. Last weekend I tried drowning the ants by completely submerging the container in water for an hour or so. They survived! There must have been some air bubbles left behind in the soil so they could keep breathing...
What else could I try? I don't want to poison the soil of the plant...
My next step will be to put an ant trap in the container. I'm just not sure these traps are really effective. If the ants aren't gone by the end of the season I will again try to get rid of them by replacing the soil, and this time also by rinsing the root ball with a water jet. Is the ants do return after that, I won't take the plant inside again. And that would really be a pity as it is one of my nicest growing citruses!