I am really baffled as to why all my shrimp recently died. I even purchased more and same thing happened. It’s really sad and i would like to get it figured out before i cause any more to perish.

Here are some initial specs on my tank.

Nitrates 5ppm
Ammonia 0
Phosphates 1 ppm
Ph 6.8-6.4 (depending on co2 levels throughout the day)

I dose excel once a day at double the recommended value.
And micro ferts 3x weekly.

I use mixture of tap and RO with dechlorinizer and GH booster.

Any help would be appreciated.

Thanks!