First post here. I had a 125 gal aquarium with sand substrate and Live plants and healthy fish. We built a new house and I didn't want the hassle of moving the whole set up, so I bought a new 125 tank. I wanted my plants to grow better so I used a base layer of fluorite and then covered with Eco complete. I transferred 50% of my existing tank water to the new tank and moved the bulk of the plants. I bought a new canister filter because I knew I could move everything at the same time. I waited two weeks then moved the majority of the fish. The tank started to go through a mini cycle. (I was hoping it wouldn't with the BB in the Eco complete and moving the live plants. Ammonia went up to .25 seen .5 one day Nitrite .25 and Nitrate went to around 50. The tank started to get a haze I assume from the growing BB. For the most part the fish seemed fine then a few started hanging out near the top. Then I started to have a few guppies, neons die each day. So I hurried up and moved the rest of the fish and brought the canister filter that was on the established tank and installed it on the New tank. By the next day the haze was gone. I am at about week 5 of the new tank being set up and fish continue to die. Some seem to have bladder issues and either sink or float before they die, some don't seem to have any issues. Last night I noticed my clown loach was acting strange today I get home and he was dead covered in a white slim (I have never seen this slime before) All the plants seem to be severely melted with know new growth. I use 10mm of metricide 14 each day. All the corys seem fine, BN pleco seems fine Amano shrimp seem fine, Kuhli loaches seem fine Most guppies seem to be staying near the surface. Neon schooling and seem ok but seem to have one die every few days. I would guess around 20 fish and died in the last few weeks I did add a few new fish they seem fine. I have my UV light on incase of parasites. Please give me some advice this is getting really frustrating.