I'm sure a lot of this has been covered in previous posts, but I also realize that each situation is different and I'm hoping somebody can help me (assuming I have a problem). I simply can't get the tank to cycle. Using the API Freshwater Master Test Kit, my ammonia readings are generally between 0.25 ppm and 0.50 ppm (maybe slightly higher before a water change). I never get readings for nitrites or nitrates and it's been about seven weeks now. Details to follow:
I just bought my very first tank (55 gallon) in December and set it up right after Christmas. It's a family tank and my son is in charge of the decorations. We added black gravel (with a little white mixed in), some fake plants, and a few store-bought items like a volcano and house with a wheel. We have two heaters and a Penguin 3000 filter (I think that's what it was - supposed to be suitable for up to 70 gallons).
The first thing I read about starting a tank was to cycle it with fish. So, that's what I did. I bought six platies. After a couple weeks, two of them died. The rest seem to still be doing fine even after seven weeks or so. I also ignorantly listened to a pet shop owner a couple weeks ago who told me it was OK to buy a koi angelfish. While I now regret the purchase, the angelfish seems to be doing fine and the five fish are living harmoniously in the aquarium.
I feed them flake food once per day - usually about 7 p.m. or so. I try not to overfeed them, but I think I may be doing so (slightly). When I feed them, they seem to eat a bit. Usually a couple flakes don't get eaten, but not many and I try to give them less so this doesn't happen.
Up until this week, I've been doing two water changes per week - typically about 20%. I tried to do them when the ammonia level hit 0.50 ppm. The first few weeks, the ammonia level would typically go down to 0.25 ppm after a water change. Now, it seems to stay right around 0.50 ppm.
The pH level usually went down after a water change after adding the salt conditioner stuff (fluctuating between 7.0 and 7.8); however, the last week or so, the pH has been 7.6 or higher. I just did a water change last night and the pH is still over 7.6. If it gets too much higher, that would be really bad for the fish, right???
The last detail I can think of is that I recently changed the filter pads in the filter. I read somwhere recently that I shouldn't have did that and I may have killed any beneficial bacteria in the tank. When I changed the filters, I did run water from the tank through them, but didn't save any of the old filter to put behind the new filters or anything like that.
So, after all that long-winded explanation (and thanks for reading that far and putting up with me if you've made it this far), am I just being impatient? Am I doing something wrong? What should I do? Do I need more fish? Less fish? Different fish? Do I need chemicals?
Any advice or help would be greatly appreciated. I look forward to having a nice, healthy tank for my son and family. If I ever get this right, I'd love to start a smaller tank, too.