Frustration

[Barrett.Oliver]

Alright Ladies and Gents,

I've been having such a terrible time with the tank I have set up about 5-6 weeks ago. I'm losing the livestock that I put into it. I have tried a Clownfish and a I have also tried a Cleaner Shrimp. The fish ended up with the velvet on them. I'm not even sure what happened to the shrimp he just stopped moving(this was before the fish died). The water as far as I can tell couldn't be better. The ammonia is steady at 0, as are both the nitrite AND nitrate. pH holds at about 8.0 (give or take 0.5 each time I test it). I'm also changing the water with RO water every week (apprx. 15%-20%). As far as I knew this was the correct way to be doing things?? So I guess what I'm looking to figure out, if anyone know why the animals I've nemed are dying or is this something that is case sensitive? I've has some snails in the tank all this while and nothing has happened to any of them (that I can notice that is). I've read nothing about why this may or may not happen. So any insight would be greatly appreciated.

Thanks,
Barrett Oliver