Ammonia problem?? Please help
I have a 20 gallon thatís currently having a huge ammonia problem, the levels are off the charts (Iím using API Ammo Lock to the ty and keep my fish from dying) and I need to move some fish out. The ammonia levels are measuring at 4ppm. Iím using the API Freshwater master test kit. I did a 50% water change last night and right after and this morning the ammonia was measuring the same as before the change. Iím going to be doing 20-25% water changes every day for the next week.
Another thing is that I changed the substrate of the tank last week, from gravel to to sand. It wasnít live sand, but it seemed to be fine and I added API quick start to replace the lost bacteria.
The fish inside are 4 Dalmatian Mollies, 6 Kuhli Loaches, and 3 neon tetras. Thereís no live plants. There was a snail in there too, but last night they died.
I have a small 5 gallon that has never had any fish and has been cycling for at least 2 weeks now, but when I went to test the water to see if I could move the tetras into it to relieve some stress from the 20 gallon the water measured at 1-2ppm of ammonia!? Thereís no reason for there to be ammonia in that tank that I can think of. I donít know what to do to fix this. None of the factors that could be affecting the 20 gallon should be affecting the 5 gallon.
I tested the tap water from the sink I use to for aquarium water and it didnít have any ammonia in it, so Iím not sure where itís coming from.
Please give any advice you can