9 day old chicks COCCIDIA HELP

[Feathered babie]

January 19th I purchased 10 baby chicks from Rural King. They started dying I’ve lost 3 and today 1. After finding out about the coccidia late (I’m new to this) I started them on Corid H2O yesterday. One of them I had to basically give triage care. It seemed to have worked it perked up was weak but eating and drinking when I offered while holding. He made it through the night today and seemed better this morning. When I checked him again not too long ago h was getting stiff, gasping and neck backwards. I am heart broken an can’t stop crying for these little souls. I’m so scared for the rest they are doing great eating drinking but this one passing tells me they’re not safe. I’m doing everything I should be I don’t sleep taking care of them this is a nightmare. Someone please help. How long should I do the treatment for I found online 5-7 days but 5 being the regular 7 with less Corid to avoid reinfection. What amount of Corid to what amount of water has worked best for you. Anything that helps I need help this is so unfair to these little souls. Thank you