I had to set a tank for the few carbon rili I had left. The shrimps were passing away one by one in a tank where I could not find any reason why they were doing so...
I an emergency rescue, I dressed a new tank, 30liters, new soil, plants, new sponge filter, and I dosed some Bio Nitrivec (SERA). 2 hours after, I moved the shrimps in that new tank, and crossed fingers...
That was a success. Not only the shrimps stop quiting, but they start again breeding after few weeks, and now I have recovered a full healthy colony from the very few I had left (3 females 4 males). They are about 400 now ^^)