I have now used Thrive in my tank 4 times now. I have a 29 gallon tank but I only have about 21.3g of water after I subtract subtrate. So I've only been dosing based of 20 gallons of water. I've tested my water and I have 0 ammonia, 0 nitrite, 10 nitrate which is pretty steady. Out of the the last 4 times I've dosed Thrive, I've had dead fish within the next day or so. 3/30 @ 5:18pm, did a 14% water changed, added Thrive for the first time, 2.8ml 3/31 @ 9:04am, had a dead pygmy cory, no visible damage. 4/3 - Started adding Enhance daily, 2.0 ml per day. 4/4 @ 8:53am, did a 28% water change, added Thrive for the second time, 2.1ml (no dead fish) 4/7 @ 2:30pm, did a 28% water change, added Thrive for the third time, 2.1ml 4/8 @ 7:26am, two Golden oto's passed, no visible damage. 4/11 @ 7:47am, did a 28% water change, added Thrive for the fourth time, 2.1ml 4/11 @ 1:45pm, noticed a Rasbora struggling to swim at the bottom of the tank, laying on his side or upside down, looking pale. Shortly after that the Betta and Loach started picking at his almost lifeless body and he was a goner. So I'm getting worried here. When I test my water, I don't see anything that is of cause for concern. Ammonia is 0, nitrite is 0, and the highest I've ever seen my nitrate was a 10. I usually test as soon as I see a dead fish or a fish struggling. I always treat my water with Prime before It goes in during my water changes and it's always about the same temp as the tank water, 77. Could there be something in Thrive that just don't sit well with my fish by chance? I'm really quite scared to keep using the product because 3 out of the 4 times I've used it I seem to have lost fish. Thoughts?