Ph Dropping Fast

[qingwei789]

Hey guys, I have been stuck with this problem for about 3 week trying out various method mention online but the pH is still dropping.
Methods that I have tried are
1stly : Reduce the amount of food fed to the fish
2ndly : Increase the aeration (remove CO2)
3rdly : Increase limestone (increase calcium carbonate, act as a buffer towards acid)
Lastly: Changing of filter* (The last thing i did before I posted this)

As I proceed with these step, i have been changing the water frequently to maintain the pH level.
Originally I tried to maintain pH at 6.0.
Once i changed my filter, the pH rise back to neutral and it starts to decrease again and now is it at 5.4. I only changed my filter last week.
*pH meter seems to be working, used on a buffer solution and it shows the correct value i.e. pH7.

Someone please save my aquarium

 

[three-fingers]

Lots of questions to ask first! What fish are you keeping? Also what is the size of tank, stocking levels and what filter does it have? Do you have any wood in the tank?

Have you tested your tap water for pH and KH? The KH is what keeps the pH stable, you should test your tank for this too .

pH 5.4 is low for most tropical community fish, though not necessarily harmful depending on what species. Angelfish, discus, rams and loads of tetras could thrive at that pH - so don't panic yet!

If nothing in the tank is releasing acids and you are doing enough water changes, I would expect the pH to be much higher though, unless your tap water is already soft and acidic.

edit: Also, when you say "change the filter" do you mean you cleaned it out or literally changed the media for new stuff? Did you change all of it or just some?

 

[qingwei789]

Hi three-finger, thank you so much for the fast respond.
I'm keeping small tilapia about 2cm in size, 30 of it.
Size of my tank is about 72 x 60 x 45 cm
There is no wood in my tank but i do place aquatic plant in it
I have measured the pH of tap water to be about 6.8pH.
The hardness in my tank is about 100ppm CaCO3
I changed the filter media inside my filter.
Im worrying about the nitrifying bacteria, as I saw online that nitrifying bacteria dies off at pH below 6

I will check out the kH ASAP

 

[three-fingers]

Luckily enough, at a lower pH, ammonia is much less toxic to fish (as more of it is in its ammonium form), and if you have plants that are thriving this will be used as food for them too.

I would be more worried about the filter media being changed - as this is where all the nitrifying bacteria live - so if you threw it away and replaced it with new stuff, most of the bacteria have gone with it.

As your tap water is at pH6.8, it is probably quite soft too, both in GH (general hardness) and KH (carbonate hardness) so with all the acids being produced by your fish and bacteria in your aquarium the pH will drop.

If the KH was higher, it would remain stable at pH6.8 (or higher, as you have the calcium rock).

The simplest remedy to keep your pH stable would be to add a small measure of sodium bicarbonate (baking soda) to the water before you put it in the tank during water changes. After a few 25% water changes with this, the pH should be nice and stable . Dosage information for baking soda can be found here: http/dataguru.org/misc/aquarium/CalKH.asp

But it is very important you test the KH first and continue to monitor it every water change just to make sure your not overdosing .

 

[qingwei789]

Thank you very much for the tips I will try these out ASAP

 

[TwoTankAmin]

A couple of observations:

First, the bacteria in a tank will be all over, on all the hard surfaces, not just in ones filter(s). The heaviest concentrations will always occur where the best supply of food and O are. While this is usually one's filter(s), it is not the only place they live.

Second, adding baking soda will have two effects:

To raise the KH without raising the GH, add sodium bicarbonate (NaHCO[sub]3[/sub]), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.

While the GH may not change, the TDS levels will.

I recently was dealing with chemistry issues regarding simulating rainy and dry seasons to trigger fish to spawn. I needed to raise the TDS levels for the dry season. I used a mix of calcium carbonate (via crushed coral), Epsom salt and baking soda. I pretreated the changing water going into the tank. What I discovered was I could test the tank levels with my TDS meter an hour after completeing the wc with the treated water and get a reading, However, the following week when I again tested the TDS prior to doing a water change, the TDS had risen between 10 and 15 ppm from the prior week's after wc reading. There is some lag effect at work.

 

[qingwei789]

Hi guys,
Thank you so much for the help. The pH has raised to about 7.2 after adding the baking soda.
Feeling much more relieved

However, I have some questions to ask.
Is there any side effect on using baking soda? Except that it may cause pH to increase too much -> ammonia become more toxic.
Is there a difference in adding lime stone compare to baking soda?

Once again, thank you guys so much for helping out

 

[snazy]

If you have removed your bacteria via the filter media change, or if most of it has died because of the low ph, then simply raising the Ph with baking soda may cause even more trouble with the ammonia converting to toxic and non-stable Ph throwing your fish in shock. Adding baking soda is not a solution, it just works like a pain killer when you have pain and you take it every time the pain hits you, but you need to fix whatever is causing the issue.


How long do you have the tank set up? What is the water volume? How many litres/gallons an hour is your filtration? What are your weekly/biweekly readings of nitrates? Are you adding ferts?

 

[three-fingers]

Is there any side effect on using baking soda? Except that it may cause pH to increase too much -> ammonia become more toxic.

As long as you don't use too much of it at once and mess up the pH and KH massively lol. It's just sodium bicarbonate - sodium and bicarbonates are found in natural waterways in lots of different forms .

Is there a difference in adding lime stone compare to baking soda?

With limestone, your GH would increase as well, due to the calcium and mineral impurities in it. And the KH would be affected much, much slower as obviously rock takes a long time to dissolve compared to a pure powder.

If your plants are growing well and you have no dead fish yet you shouldn't worry. Maybe add a teeny amount at water changes if you test and your pH is back at below 5.5, but otherwise just keep up the frequency of water changes and try to get the plants to grow well, as they will look after your water, and in turn your fish .

 

[qingwei789]

Hi snazy,
My tank has been set up for about 6months.
My filtration rate has no indication.
I take nitrate reading every week, currently it is about 100ppm.
I believe the nitrifying bacteria are still there because my nitrate level is still increasing after i changed my filter 3weeks ago.
I do not add ferts.

I have been trying to find the root of this problem.
It has been about 1month since I started my investigation.
I have look through various aquarium websites but still no solution stated by them is valid in my case.


three-fingers, Thank you for the advice

 

[snazy]

You have 100ppm nitrates after water changes and such, so they must have been even higher maybe?
When the tank is exposed to high nitrates for a long time, the water loses buffering ability and eventually the Ph will crash. This is very normal in these conditions, but it's hard to get out of it and your fish will go through a horrible ordeal. Baking soda will help for a while, but the Ph will again crash and it's hard to keep a stable Ph with baking soda
Your only bet is to properly siphon the gravel to remove any waiste that will turn into nitrate eventually. Make sure your filter parts are doing their job and are not full of large particles. Well, don't wash you pads in tap water though. You tank is only 6 months old, but it seems either the filter capacity or maintainance is not enough. Add a second filter to help with the accumulating waiste in the tank, as even if you had done regular water changes in the past, the amount of particles fallen between the gravel, will cause nitrates to rise rapidly regardless. And then start doing water changes everyday to increase the buffering capacity naturaly. Do the water changes for as long as you can. You need to bring that nitrate reading to 0-5ppm max for the time being, once problem is solved, keep it below 40.
Don't worry about the bacteria at the moment. If water changes everyday are done to fix the Ph and nitrate issue, and Ph starts going back to normal, then the water changes will also help with the mini cycle. Fish will suffer one way or another unfortunately and Ph swings kills them faster than any ammonia/nitrite.

Edit: You would want to start off with a massive water change to lower nitrates to as little as possible, or 2 water changes in a row. Pour the water as slow as possible to help the fish adjust to the different Ph of the tap water, take your time really. Then keep doing big water changes every day.
Monitor your ammonia/nitrites too in case there is a cycle issue.
You'll be swimming in as much water as the fish till all of this is fixed

I see that you have actually changed the filter, if it is any better than the previous one, it may prevent future problems like this once this is solved.

 

[three-fingers]

Remember nitrate is non-toxic and can be found t very high levels in tap water - 100ppm isn't that unusual for some places. Check your tap water nitrates before tyring to lower them.

If your nitrates are already at 100ppm out of the tap you could change over 100% of the water and see no improvement.

The nitrates could even be over 100ppm and the plants are lowering it from tap water levels .

Also pH swings are nothing to fish compared to ammonia and nitrite poisoning though . Natural waterways drop in pH very fast after the sun goes down every day, and the pH rises fast in the afternoon.

No knowing your filtration rate isn't good though, as Snazy mentions, you could possibly do with another or a bigger filter.

What filter model is it and what are the numbers on the side?

 

[snazy]

I think 100ppm is quite toxic even to humans, so chances are tap water has way lower nitrates

 

[Rummynose]

I think 100ppm is quite toxic even to humans, so chances are tap water has way lower nitrates

I agree with snazy, nitrates are toxic also, but not in the same level as ammonia and nitrite.
I also believe that ph yo-yo is very bad for the fish, it is better to let them adjust to a low level ph in your tank than to try balance it chemically! You just have to really take your time when adding any new fish to your tank.

Both my tanks have very low ph, all my fish are doing very well. One tank measured 5.5, the other 6.2. Tap water is 6.5!!!

 

[snazy]

I agree with snazy, nitrates are toxic also, but not in the same level as ammonia and nitrite.

I meant that it is highly unlikely the tap water to have high nitrates, because nitrates although not as toxic to fish, are actually toxic to humans.

Reason Number 1 for Ph crash in fish tank is high nitrate build up in aquarium, whether from waste,incapable filter, or irregular water changes, etc...

I understand that fish can adjust to a high range of Ph,but the Ph needs to be stable. A Ph that crashes like that is not normal for a healthy tank and needs urgent addressing.

Also pH swings are nothing to fish compared to ammonia and nitrite poisoning though

Buy a new fish that was in a 7.6 Ph and put it straight from the bag to a 6.0 Ph let's say, presumably the water temperature is the same. What happens?

That's why we acclimate fish and so on. Fast Ph swing kills the fish faster than ammonia and nitrites.

Of course, if Ph changes over long time, then the fish adjusts and eventually it don't matter that much unless it starts changing regularly.