BigJoe

Ok so if your read my post in the beginners section ou know that my tank went through a major pH drop and killed all my fish... thinking this was due to a mini cycle i added some more... they all died in less than 2 hours... that was about 2 weeks ago... i have been doing water changes every other day since but i guess since my tap water is measuring between 6.4 and 6.6 that it wasnt enough to bring it up... maybe even making it worse... today i got a API Full test kit and some PH up... my PH is now registering 6.4 but with the little extra i added of PH up i expect it to go a little higher before morning... since this was done... I decided to test for my other parameters... well either my cycle completely crashed from not having fish in there or my PH killed all my bacteria... i am registering 1ppm ammonia and everything else is 0...

About my tank and inhabitants...
14g w/ 150gph filtration...
lightly planted with 3 anubias (had a crypt that melted away and i figured that was cause of PH drop, and my java moss died i'm guessing from lack of nutrients... )
no current fish die to rapid death of "test fish"
total lost fish since start of problem: 6 serpae tetra, 3 cories, about 8 ghost shrimp; after they died 3 neon sized green tetras with fire tails, 3 cories; then 3 glofish... all acclimated for an hour min. ( some died in acclimation)

my question: can PH lower than 6.0 kill the bacteria (makes sense to me if it would..)? am i going to have to completely recycle my tank... do i need to take all my plants out? do i really need a hardness test to figure out my problems completely?

clinton1621

No pH lower than 6 just by itself will not kill the bacteria or the fish.... however if your water doesnt contain enough buffers to keep the pH stable, then pH swings WILL kill the fish but not the bacteria. You really shouldnt use the pH up products... they will only cause more pH swings because they are not fixing the whole problem. I would recommend that you use some crushed coral or limestone rocks in the tank, this will slowly bring your waters hardness and buffering capacity up and safely raise the pH without rapid swings. You also may want to look into using gallon jugs of mineral or spring water to fill the tank... this type of water will have a much better hardness and buffering capacity than your tapwater does.

Also take a look at this thread, it may help explain things a little clearer for you....

Changing your pH

BigJoe

ok so it seems the limestone worked... (i hope this worked at least for now) my question is that now that it is in there i like the look of it and can I keep it in there? or is it gonna make my ph keep going up... is this solution only for short periods when i have problems and if so what is a more permanent solution?

BigJoe

oh and i thinki over cleaned my gravel is the reason my cycle crashed

clinton1621

You can leave the limestone in there for as long as you want, it dissolves slowly so its not going to overly buffer the water, especially not if you do good water maintenance =)

sirdarksol

Technically true (given the time frame we're talking about. Long-term, like months or so, 5.9 most definitely can kill), but a low pH like this will seriously stress the fish (as will the lack of minerals, if the fish are normally hard-water fish), and can open the way for infections and parasites.

BigJoe

ok... one more question... i have no fish in my tank and haven't for about a month now... why do I have high ammonia? do plants put off a lot of it is it possibly from bacteria dieing from not having enough to live?

sirdarksol

Ammonia still shouldn't be remaining high. The bacteria, as they die off, will release ammonia back into the water, but the surviving ones will consume it. By the time they've all died off, there should be a minuscule amount of ammonia in the tank. It should have all been turned into nitrites and then to nitrates. Likewise, the plants should be absorbing it, unless they're dying off.
What kinds of plants do you have? What lighting do you have? What kind of substrate? Are they being given supplements?

clinton1621

Isnt that basically what I said, just worded differently lol.... I covered the buffering capacity, which would be the lack of minerals, I did leave out the part about mineral deficiency though...

sirdarksol

You said that it was the pH change that would hurt the fish.
While that will hurt the fish, it's not the only thing that will do so. The osmotic stress and low pH will, in the long run, be harmful in their own rights (though, I agree, not as harmful as a series of pH swings would be).

clinton1621

I completely agree, I guess I did underexplain a little lol... thats why I recommended he use limestone or crushed coral to raise the mineral content and pH of the water. I'm still not sure about his ammonia problem, especially with no fish in the tank... the pH levels really shouldnt affect bacteria right?

Edit : My line of thought is also the plants decomposing for some reason.

BigJoe

thats all i can think of too... i mean with as much as i vaccumed i cannot concieve the fact that there is still fishy parts in my gravel... now i'm waiting on the amonia to start going down so i can add a fish for a test and to keep the cycle going... i would assume there is still some bacteria in one of my filters... I intentionally washed the other flos as it was so dirty i thought at one time that could have been the cause... and the water i pulled out wasn't cleaning anything...