I feel your frustration man.
I've lost more than 100 tigers/super tigers.
First batch was 30 super tigers, they died slowly about 2-3 a day.
Second batch 100 super tigers/regular tigers; they died 5-8 a day around 6 left.
The first two batches of tigers I just drop acclimated for around 4 hours from main tank.
Main tank is a 100gal planted tank with CRS, PFR.
Recent batch 50 super tigers/regular tigers
The thing I did different with this recent batch.
1. Quarantine tank 5 gal with moss, java ferns on drift wood and a sponge filter.
I used Ro water and adjusted TDS to 150 with conditioner.
Seeded sponge filter with old tank water and quick start solution.
Quarantine tank is about 4 days old.
The day before you receive your shrimp dose a full dose of paraguard into the tank to kill existing bacteria from old tank.
2. Test TDS with meter and adjust TDS of quarantine with water shipped with shrimp.
The tigers bag water was 200 I adjusted quaratine tank from 150 to 185
3. Dose melafix first day 1/2 dose
Second day rest
4. Dose seachem paraguard (third) day
I'm on the 6th day now, they are still in quarantine.
I dose paraguard every other day 3/4 dose
Everyday before dosing medication I take out about 1 gal of water from the quarantine tank and add 1 gal of water from the main tank.
So far so good no dead tigers this time.
The tigers I got were all in the mail for (9) days.
I've read so many threads online about why you should or should not acclimate shrimp or quarantine shrimp.
I saw a thread from a german guy (wish i remembered the site) that says every tank has their own composition of bacteria and diseases.
Shipping is always stressful for shrimp and will lower their immune systems.
Makes a lot of sense if you ask me.
This has worked for me maybe you should try it with your next batch of shrimps.
I have 8 Tigers from the 1st and 2nd batch left and one female is berried...
These 8 tigers were probably the strongest out of 130 shrimps but if I paid extra attention to them I would have 100+ tigers now....
Losing the shrimps was a little painful and stressed me out a bit but I learned SO SO much more from it.
DON'T GIVE UP!