Hey guys. I'm pretty new here, and I'm almost at the point where I'm ready to pack it up and call it quits with my tank. I've had a freshwater tank running since May 12th. I had initially started with ATM Colony (I now know more about fishless cycling and that sort of thing - if I were to start over I'd go that route for sure - can't change the past) and three neon tetras (with intentions to add more in a few days) and two corydoras. I lost a tetra a day for three days. I was obsessively checking the water with the API master liquid test kit. I ended up adding another corydora and 6 Danio (3 zebra, 3 glofish) after waiting it out for a week or so. We did have an ammonia spike within the first couple of weeks (I think I overfed and probably messed up any benefit I'd have gotten from the Colony) so I did a ton of water changes until I had it under control - it was pretty grueling for a while, but I felt awful for the fish. We lost one of the Danio and an albino Cory. Other than that one spike I have not had a problem with my water. I test regularly. I have added some seachem neutral regulator a couple of times to make sure it didn't get out of hand though it never seems to get particularly high even when untreated. We live in a rural area of NS and have well water. Before getting the fish I was pretty content with our water quality - husband is a plumber and he had taken a water sample for testing while upgrading for his license - it's great water, and I knew I wouldn't have a lot of issue with that. Since that one spike in quality I've added two more corydoras, and two Kuhlis. One Kuhli died within a week, the other lasted a day shy of a month. Last weekend I picked up a few more fish - 4 neons (figured I'd give them another shot) and 2 panda cory. I was super excited for the panda cory because I live 3 hours from the nearest city, and have one small lfs in my area and I had never seen them there before. One panda and one neon died overnight. The remaining tetra seemed fine. I went back to the store and got 3 more tetra. The owner said that she had lost a panda as well - so it's possible that there was an issue with the shipment. This was Saturday. It is now Wednesday, and I have no neons in my tank. I also randomly lost a danio last night. Currently I have: 4 corydoras and 4 danio. I'm afraid to add new fish because I don't understand what I'm doing wrong - but I also know I should get a few more danios. I do weekly water changes, probably around 20% - occasionally more. I tested my water last night - today is water change day- and the ammonia was reading below .25. The nitrite is 0. Nitrate may be SLIGHTLY above 10 - definitely under 15. Ph is 7. Temperature is 78. HOB filter - I rinse the bag and sponge in aquarium water when I do changes. The equipment was only purchased (new) in May, and seems to be running without issue. Water has been giving consistent readings for a month or more. Acclimation of the fish takes me around 1-2 hours. I float the bag. I add water very gradually- starting with a 1ml eye dropper and slowly moving up to more and more water. When I change the water, I make sure the new water is as close as possible to the temp of the tank. I honestly don't know what I'm doing wrong. Around the same time I bought my tank, my sister in law bought one second hand with all the equipment and fish. She's lost one fish. I don't think she's ever tested her water, and pays minimal mind to the tank in general. I read for months before getting the tank about fish that I wanted to get - what they would need, what would be compatible tank mates, etc. I tossed the strip tests within a couple of days of using them in favor of the liquid ones because they're garbage. I acclimate slowly. I do regular water changes. I have a couple of live plants with plans to add more. I hate knowing that I have fish that are suffering. I feel horrible. When I search online for possible tips/ answers to the problem, I'm really only finding posts about people who have only had a tank running for a week or two that clearly hasn't cycled or who are putting fish into the tank straight from the store. I'm going absolutely crazy trying to figure out what is going on but as far as I know I'm doing everything right. HOPEFULLY someone can point out an error with what I've been doing, or give me some sort of advice other than "read about the nitrogen cycle" because I've done an awful lot of reading, and the consistency of the tests point to my tank having finished cycling weeks ago. If there's something off about my water / cycling please let me know specifically what you think it could be. Like I said - I'm new, but from what I've read I am doing a pretty good job of staying on top of things.