HELP Qns on shrimp set up

[tung hu]

hi all, have tried setting up a shrimp tank twice but failed. 1st set up is with old magic soil some moss and a small filter. soil was from 1 of my friend cause he gave up his collection so i took over add all the stuffs and run for 3 days then introduce shrimps in but less than 1 month shrimps all died. 2nd attempt is change all the soil to those black kind of gravel (not soil) run for abt 1 week but end up still the same out of 20 shrimps now left 3 or 4. 5 otos are doin fine. can any1 pls enlighten me for the setup.