Jump to content
Kokos Goldfish Forum

Help with persistent low PH

Recommended Posts

Ive been struggling for about a year, ever since I set this tank up, with very low PH. I have never had this problem before with other tanks. There is obviously something in my set up that I'm missing that's causing the problem and I'm looking for any help diagnosing it.

I have a 240l aquarium, that houses 2 medium fancy goldfish and 2 small fancy goldfish.

It has a 306 Fluval external filter.
For decor it has sand as the base, is very heavily planted and a few stones and an aquarium safe, fake branch
I did have some driftwood in the tank though I took that out a few months ago as I thought it might be the culprit, but no difference.
2 large bubblers.

The water quality just tested as aminia 0.2, nitrite 0, nitrate 0, PH 6.8
The temp is a bit high as its very hot here 28'C. I have added in a couple of bottles of freezer cooled water to cool it down.

At the moment I'm having to put PH up in every few days to keep it up.

The only differences in this tank set up that ones I've had before is I've used aquarium sand for the first time, an it's much more heavily planted. But as far as I understand they shouldn't' lower PH?

All ideas welcome. Or let me know if you need any more info.


Share this post

Link to post
Share on other sites

Use baking soda (sodium bicarbonate) .  Draw a known volume of tap water into a bucket.  For example, 20 liters.  

Read and record the pH.

    Add a known volume of baking soda -- for example 1/4 teaspoon.   Record how much you added.

    Give it a few minutes to completely dissolve, then read and record the pH.

Repeat this procedure (adding baking soda and reading the pH) until you get the desired pH.  Most people like pH 7.5.  

    Add up the total amount of baking soda you have added.  That's how much baking soda you will need to add to each 20 liters of tap water for your water changes.  


You could multiply that by 12 to determine how much you would have to add to your full tank.  However, you don't want don't want to add to add baking soda to the tank all at once since you can shock the fish by rapidly changing the pH.  

I suggest you add the amount of baking soda that you needed for 20 liters of tap water to the fish tank daily until the pH reaches your goal.  After that, add the baking soda only to your new water when you do a water change.

How often do you change water and how much do you change each time?





Share this post

Link to post
Share on other sites

I change about a third of the water, about every 6 weeks. My levels never get very high at all, I think the low PH might be stopping is cycling properly.

Thanks for the tip about baking soda. At the moment I use a product: PH UP from API (https://www.apifishcare.com/product.php?id=645#.Wzp-dcIh1aQ) to keep the PH up. Ive done a similar method gradually bringingit up.  But it can quickly fall to 6.0 if left unmedicated. But even when I get it to 7.4 or so, where the goldfish are happiest, I struggle to keep it there, so I'm guessing there is something wrong in my set up.

Share this post

Link to post
Share on other sites

Please read our guidelines for healthy goldfish.  Pay attention to the information on water changes. 

Acceptable levels are zero ammonia, zero nitrite, and no more than 20ppm nitrate.  If the nitrate goes higher the pH will drop.

API doesn't give the active ingredient in pH up, but most people who use it think it is baking soda.  I can buy 5 pounds of baking soda for less than $4, and if I had to use it in the tank, one purchase would give me more than a lifetime's supply.


Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...