I have been having major problems with a 5 gallon. I have had several different fish in. Anything but goldfish die. I bought my daughter a beta and put in it and his color got awful and I knew I was about to lose him. I went and bought a 1 gallon set up and got it going and dropped him in. Within a day, his color came back and he is eating fine. 
I tested the 5 gallon before I put the beta in and it seemed fine. The nitrates were a little high, but not leathal. There was an algea problem in the tank for she never turns the light off. We are getting better with it with the 1 gallon. Since setting up the small tank, I have washed the 5 gallon thouroughly, again. Along with the filter and heater. I have let them set a week to dry and am now ready to set it back up. I discarded the gravel and decorations. So I guess what I am asking is would the gravel and other things hold chemicals or whatever is killing my fish? This is the first time I am setting back up with fresh garvel. What I am wanting to do is set the 5 gallon back up and use as a nursery with my guppies and platties. By putting the very pregnant mommas in there and then take them back out after giving birth. That way I can save more babies. My wife works at a small school and each class is going to set up an aquarium and I plan to supply them with fish. So the more I can breed the less it will cost. Sounds like a plan anyway.
I tested the 5 gallon before I put the beta in and it seemed fine. The nitrates were a little high, but not leathal. There was an algea problem in the tank for she never turns the light off. We are getting better with it with the 1 gallon. Since setting up the small tank, I have washed the 5 gallon thouroughly, again. Along with the filter and heater. I have let them set a week to dry and am now ready to set it back up. I discarded the gravel and decorations. So I guess what I am asking is would the gravel and other things hold chemicals or whatever is killing my fish? This is the first time I am setting back up with fresh garvel. What I am wanting to do is set the 5 gallon back up and use as a nursery with my guppies and platties. By putting the very pregnant mommas in there and then take them back out after giving birth. That way I can save more babies. My wife works at a small school and each class is going to set up an aquarium and I plan to supply them with fish. So the more I can breed the less it will cost. Sounds like a plan anyway.
