I live in Southern California and have been working on a small balcony garden - I noticed my Vinca was yellowing (it usually thrives) and on closer inspection found ants all over the plant (but no scale or mealybugs) and a colony of tiny grey insects underneath the pot, with a ton of white eggs around the drainage hole. I doused them in a soap/alcohol spray and repotted the plant - no sign of any larvae or crawlers in the soil itself, but there are still ants and the tiny grey bugs walking around, and I see the grey ones have taken up residence under my aloe and my dwarf pomegranate.

Any idea what these could be? Are the ants farming something down there?

The grey bugs are really small (hard to see unless there's lots of them), do not have wings, are sort of oval shaped, and seem to have long feelers out front. The eggs were white and pretty large by comparison, clustered around the drainage hole. I wish I'd taken a pic before I destroyed them!

The Vinca pot is no doubt the best watered on the balcony, so I guess they like the moisture, but even so I only water when the soil is dry and it's been consistently 80-90F here until very recently so without regular watering the vinca would perish...

Thanks in advance for your help! Google has furnished nothing so far...