Trying to adjust PH up, with little success

[GBBUDD]

If you are fortunate enough to have tap water that has good parameters, then water changes can help somewhat. That is not the case with the OP.

Please realize that even with water that has a higher pH, doing a 20% water change will change those parameters by only that same 20%. That may not be enough to increase the pH to a safe level.

Agreed. Ammonia nitrate and pH are the everyone tests for. And that's only because they are the first signs of trouble. So kinder garden through 5th grade.

Now comes putting all the basics you have learned into creating a viable habitat for your pets. 6th grade through high school.

Say you added 50 pounds of baking soda to a 1500 gallon pond. " do not do this you will kill everything" if done all at once.
Your pH will rise to 8.3 and that's as high as it will go add 200 pounds and 8.3 is as high as your pH will go.

But what will continue to increase in your Carbonate hardness. "Kh" with low kh your bacteria can not thrive if your bacteria can not thrive your fish and environment will not be healthy.

As mentioned kh also will buffer acid rain. It more than just dilutes the acidity it gives you that buffer where you will stay pH above 8.3 so if you bring your kh up to 200 or more your bacteria is thriving .

So some major thunderstorms can dump on you and your pH will stay above 8.3 now you have a masters degree in your pond.

 

[WaterGardener]

I think there are exceptions though. From what I understand, and I could be completely wrong, if there is not enough calcium in the water, the pH can continue to rise above 8.3 and will keep going up.

That seems to be the exception and unusual for water to lack enough calcium to prevent that from happening, but it can be the case. For the most part, once the pH reaches 8.3, it will not go higher, no matter how much baking soda is added, as long as there is sufficient calcium in the water. So once your water reaches that pH value, you don't need to be so careful about how much baking soda you add.

Just to be clear though, no one is advocating that anyone add enormous amounts of baking soda to your pond. There is such a thing as too much of a good thing!

 

[GBBUDD]

not enough calcium in the water, the pH can continue to rise above 8.3 and will keep going up.

i had not heard that before . i guess my calcium is good my ph never rises above 8.3

 

[j.w]

And then there are crushed oyster shells,hmmmmmmmm?

 

[WaterGardener]

Oyster shells take a long time to dissolve and they won't dissolve unless the water is acidic. At least that is my understanding.

Baking soda is cheap and easy to use and it works immediately. Once the pH and KH are at the desired levels, it doesn't even need to be dosed very often. It may need boosting when there is a lot of rain and with the passage of time, but not frequently.

 

[flboisseau]

I have added some crushed oyster shells, and they may be helping
Regarding baking soda, everything talks about hardness, which I realize will rise with that. But I am concerned about upping the PH. For example the site some one pointed me to ask me how much I want to raise the ppm KH change. I do not know that, so the calculator does me no good, I want to raise the PH to above 7. So how do I figure out how much baking soda I need to go from 6.2 to 7?

 

[WaterGardener]

That calculator will tell you how much to use. You have to fill in the areas that are listed there. Number of gallons that are in your pond, how much you want to raise the KH (carbonate hardness) and it will tell you how much to use.

That page also says to not raise the KH by more than 20 ppm per day. So just fill in the blanks with the number of gallons, use 20 ppm for how much you want to raise the KH and it will give you the amount of baking soda to use.

A pH of 7 is borderline. It won't take much to drop that back down in the acid range. Many of us here like to keep the pH at 8.2 or 8.3. And no, that is not too high. Anything above 10 is too high. But fish will live very well in a oH below 10.

At 8.3, your pond has plenty of carbonate hardness (alkalinity) to buffer the acid that is normally produced by the nitrogen cycle and by heavy rain, which can be very acidic. So there is no chance of a pH crash when the KH and pH are .much higher than 7.

The worst things you can have is a pH that swings up and down and having a pH of 7 is risking that.

I just filled in the form for you. With 600 gallons of water, it will take just a smidge over 2 ounces (a quarter of a cup) of baking soda to raise the KH by one dro, 17.86 ppm. Not 20, but close enough and that was already on the chart so I went with it.

So you need 1/4 cup of baking soda today. You can do it again each day until the KH gets to at least 100ppm. 200 is not too much.