Ph Dropped

[TheFishEnthusiast]

Hello,
 
I have a 125L community tank. It's relatively new (1 and a half month old). I woke up this morning to one of my glowlight tetra dead. A few days ago, I had my heater fail on me and had to purchase a new one (unsure if it's related). My current water is: PH 6.4 (previously 7.4 8 days ago), 0.25ppm Ammonia, 5ppm Nitrate and 0.5ppm Nitrite. The water is 27 degrees Celsius (80.6 Fahrenheit).
 
Should I be concerned about my PH drop? My fish are starting to hang around the corner of my tanks all of a sudden and near my filter. I think one of my molly is pregnant as it was releatively round and began to square off. We have recently stopped feeding the fish twice a day and went down to once as it was causing my sponge pads on the filter to turn a yellowish after being changed 2 weeks ago. We do around a 20% water change and clean some of the waste off the bottom of the tank every Sunday (Weekly).

 

[Ch4rlie]

Hello
 
Okay, I can see straight off you have a couple of issues and reasons why you tetra died.
 
First is, it certainly looks like you did not cycle your tank before you added the fish to your tank.
 
Cycling a tank, very basically, means you need to have the right kinds of bacterias in your tank and filter to be able to cope with the waste fish produces. Fish basically produces ammonia which is actually toxic to them and since ammonia is in water the fish have to swim in this stuff and its not good for them at all.
 
So therefore you need to have bacteria that can 'eat' this ammonia waste which will turn this into a less toxic produce which is nitrite, but this is still toxic so another bacteria is formed at almost the same time as the ammonia bacteria which will eventually turn this nitrite into nitrate.
 
Nitrate is the least toxic of the 3 compounds, and this is mainly controlled by us doing weekly water changes and live plants consume some nitrate as well.
 
Have a read of this, very helpful and explains in more details and also guides you on how to do a fishless cycle-
 
http/www.fishforums.net/index.php?/topic/421488-cycling-your-new-fresh-water-tank-read-this-first/
 
Of course fishless cycle means exactly that, no fish in the tank. So you may want to ask your LFS or a friend or relative who has a fish tank to look after or to hold your fish while you do this fishless cycle.
 
I would recommend you do this, as cycling a tank usually takes between 6 to 8 weeks to complete successfully.
 
You will need a source of ammonia if you do proceed to try a fishless cycle, this may help you find where to get some ammonia - 
 
http/www.fishforums.net/index.php?/topic/427161-ammonia-and-bacteria-starter-sources/
 
 
Or you could go with fish in cycling, but this is much harder work and more stressful to you and the fish as you'll need to do a LOT of water changes and daily testing of you tank water, and also this method takes a lot longer to complete, usually several months.
 
http/www.fishforums.net/index.php?/topic/433769-rescuing-a-fish-in-cycle-gone-wild-part-i/
http/www.fishforums.net/index.php?/topic/433778-rescuing-a-fish-in-cycle-gone-wild-part-il/
 
 
Lastly, about your pH drop, this could well be due to you tank set up, if you have lots of wood or indian Almond Leaves, certain substrates or sand or gravel can all help to lower pH over time. As long as the pH does not fluctuate much and stays steady for long period of time, not too much to worry about, just means you need to research a little in what fish species are suitable for your pH level, also would recommend you find out how hard your tap water is gH and kH or by finding out from your water company what the level is in your area, this help also for fish species suitable for your water type.
 
A lot of information there i know, but you will get the hang of this and it is well worth doing and finding out about, fish keeping is one of the most rewarding hobbies to have

 

[TheFishEnthusiast]

Yesterday I woke up to a shrimp dead. I think it's struggling to get food. I checked the PH prior to a water change today and it was now 7.4. I think it's fluctuating too much.

 

[Ch4rlie]

Shrimps rarely struggle to get food, especial if you feed fish in same tank or drop in a algae wafer or something as well. Shrimps find all sorts of micro foods all over the tank as well as algae.
 
Fluctuating pH is much more likely to be the cause.

 

[Byron]

I would like to add a couple of things, or emphasize them as Ch4rlie did mention one.  And that is the GH and KH of your tap water; this is very important, and often overlooked by new fishkeepers.  The GH is significant to fish, some much more than others.  The related KH largely determines your pH by "buffering" it or preventing it from fluctuating.  The pH in any aquarium will naturally lower due to the biological processes at work, but the extent to which it does this, if at all, is largely due to the KH.  So knowing this is the first step when dealing with fluctuating pH.
 
The GH is the general hardness, or level primarily of calcium and magnesium.  Mollies and most livebearers will not last long without sufficient mineral (moderately hard to hard water); tetra on the other hand would prefer none.  There is some adaptability here, but mollies cannot last in soft acidic water.  Find your municipal water supplier's website and this info should be there.
 
The other thing is the temperature.  Maintaining it at 80F is going to be harder on the tetra, and perhaps other fish that are not mentioned.  While the mollies should like this, it still doesn't need to be this high.  With any fish, the higher the temperature, the harder the fish must work just to maintain it homeostasis, which is the internal processes that keep it alive.  When these have to work harder, it puts a strain on the fish, making them more susceptible to other things such as disease.  Different fish have different preferred temperature ranges, and it is best to stay roughly in the middle of the range.  The upper and lower limits are usually what the fish can tolerate short-term but should not normally be subjected to permanently.
 
I'm just going to take a guess here, and say it is a guess so you don't run off with it, but given the pH drop to 6.4 (if that was an accurate test reading) and the shrimp deaths, your water may be on the soft side.  But the numbers for GH and KH will clear this up.
 
Byron.