First I'd like to say I appreciate anyone's time answering my ?s. I am no expert at this (new to fish tanks) and it is nice to have a community where I can solicit feedback and benefit from others' expertise. I also know that some of the things I'm going to put below were 'mistakes' (that I should have done differently). I recognize that but regardless I find myself needing advice now that I am in the situation I am.
Second, some details about my tank:
20 Gallon, Hang on the back filter (with what appears to be a charcoal bag in it), 100w heater, No live plants (only plastic)
I first setup the tank and used Tetra Auquasafe dechlorinator and also used API Quickstart for the nitrifying bacteria. Unfortunately, I only waited 24hrs after using these to introduce fish (2 mollies, 2 guppies and 5 tetra). I had not yet received my testing kit (I got the API master test kit a day later) when I introduced the fish. That first night, all 5 tetras dies and one of the guppies. The next day when I got the test kit, the water tested 8.0 on pH (which is what I assume killed the fish). The next day the pH went down to 7.8. The day after that it went down to 7.6. Then, suddenly, on the third day (yesterday) the pH went all the way down to 6. For all 3 days, the ammonia/nitrate/nitrite tests all produced zero.
I know I should have let the tank cycle (without fish) instead of taking the impatient approach, but everyone knows how the wife and family can be about not wanting to wait weeks for the tank to be truly ready for fish. That was a mistake and I recognize that now and learned from it.
When I read about 'low pH levels' most information assumes not a new tank situation. Other posts seem to indicate that increased ammonia could be causing the lower pH but with only 3 fish in a 20 gallon tank that is only 3 days old, I wouldn't think that they have peed/pooped enough in that time for that to be the cause of the lower pH (plus the fact that my ammonia test shows zero). Other explanations I've seen also don't seem to apply to my situation (old tank syndrome, needing a water change, needing to vacuum excess waste material from the gravel, as examples). These situations shouldn't really be my problem with a 4 day old tank.
Now, I am concerned about the reading of 6.0. That is as low as the test detects, so I assume it could be even lower than that. I don't want my guppy and mollies to die and I don't want to waste money on new fish just to have them die. I assume I need to get my pH to 7 (or at least 6.5) and keep it below 7.5 but the only things I see to accomplish that are things that I am not sure about. I don't want to put live plants in (which I know would be better but I'd prefer to start out managing just one living thing in here for now which are the fish). I've seen some say put crushed coral in a bag in the filter but my concern about that is whether I can do that 'wrong' and have my pH spike again too quickly for the 3 fish left.
Any suggestions? I'm trying to understand the 'cycle' here and why my pH 'crashed' overnight. I know that means that my nitrifying bacteria have (or will) die off in a low pH environment, eventually leading to ammonia suffocation for my fish, but I didn't think I should add more bacteria until I get the pH where it needs to be.
Apologies for being ignorant, just trying to figure out next steps without losing the last 3 fish. Any thoughts would be greatly appreciated.
Second, some details about my tank:
20 Gallon, Hang on the back filter (with what appears to be a charcoal bag in it), 100w heater, No live plants (only plastic)
I first setup the tank and used Tetra Auquasafe dechlorinator and also used API Quickstart for the nitrifying bacteria. Unfortunately, I only waited 24hrs after using these to introduce fish (2 mollies, 2 guppies and 5 tetra). I had not yet received my testing kit (I got the API master test kit a day later) when I introduced the fish. That first night, all 5 tetras dies and one of the guppies. The next day when I got the test kit, the water tested 8.0 on pH (which is what I assume killed the fish). The next day the pH went down to 7.8. The day after that it went down to 7.6. Then, suddenly, on the third day (yesterday) the pH went all the way down to 6. For all 3 days, the ammonia/nitrate/nitrite tests all produced zero.
I know I should have let the tank cycle (without fish) instead of taking the impatient approach, but everyone knows how the wife and family can be about not wanting to wait weeks for the tank to be truly ready for fish. That was a mistake and I recognize that now and learned from it.
When I read about 'low pH levels' most information assumes not a new tank situation. Other posts seem to indicate that increased ammonia could be causing the lower pH but with only 3 fish in a 20 gallon tank that is only 3 days old, I wouldn't think that they have peed/pooped enough in that time for that to be the cause of the lower pH (plus the fact that my ammonia test shows zero). Other explanations I've seen also don't seem to apply to my situation (old tank syndrome, needing a water change, needing to vacuum excess waste material from the gravel, as examples). These situations shouldn't really be my problem with a 4 day old tank.
Now, I am concerned about the reading of 6.0. That is as low as the test detects, so I assume it could be even lower than that. I don't want my guppy and mollies to die and I don't want to waste money on new fish just to have them die. I assume I need to get my pH to 7 (or at least 6.5) and keep it below 7.5 but the only things I see to accomplish that are things that I am not sure about. I don't want to put live plants in (which I know would be better but I'd prefer to start out managing just one living thing in here for now which are the fish). I've seen some say put crushed coral in a bag in the filter but my concern about that is whether I can do that 'wrong' and have my pH spike again too quickly for the 3 fish left.
Any suggestions? I'm trying to understand the 'cycle' here and why my pH 'crashed' overnight. I know that means that my nitrifying bacteria have (or will) die off in a low pH environment, eventually leading to ammonia suffocation for my fish, but I didn't think I should add more bacteria until I get the pH where it needs to be.
Apologies for being ignorant, just trying to figure out next steps without losing the last 3 fish. Any thoughts would be greatly appreciated.





