gypsum to lower ph

[Lindasue]

I have a 2 years old pond. I have a ph of 8.4 (at least) and total alkalinity of 240. I am concerned about ph because 2 of 3 small koi I added died. I have 5 5-8 inch koi from when the pond was put in. Most of the plants have died back to, even before it got cold.

What are anyones thoughts on using gypsum to lower ph and alkalinity? I have added 8 gallons of vinegar over 3 weeks with no change.

All help will be appreciated!

 

[Becky]

Welcome to the forum!

A little more information would be useful here - what type of set-up do you have, how big is the pond, what are your other water parameters etc...

 

[Meyer Jordan]

Welcome.
A pH of 8.4 is not considered too high. Neither is an Alkalinity of 240.
As Becky previously mentioned, more info about your pond is needed.

 

[barryian]

I have a 2 years old pond. I have a ph of 8.4 (at least) and total alkalinity of 240. I am concerned about ph because 2 of 3 small koi I added died. I have 5 5-8 inch koi from when the pond was put in. Most of the plants have died back to, even before it got cold.

What are anyones thoughts on using gypsum to lower ph and alkalinity? I have added 8 gallons of vinegar over 3 weeks with no change.

All help will be appreciated!

You said you added these small koi and the ph concerns you. As Meyer said, 8.4 is not a problem. My ph has been 8.3 - 8.4 for years and years.
The question you might ask is, what was the ph of the koi's previous home? If it were neutral, then the koi could have been slammed by the increase.
On the other hand, as stated below, more info is needed.

 

[Smaug]

Chasing pH is a waste of time for any normal fish keeping operation. Koi handle any pH as long as it isn't too low. My koi start getting flashy when I get loads of pecan tree pollen sacks in the water and it goes tea colored on me. For me that requires lots of netting,filter cleaning and water changes.

 

[Lindasue]

Welcome to the forum!

A little more information would be useful here - what type of set-up do you have, how big is the pond, what are your other water parameters etc...

The pond is about 6,000 gallons with an aerator in the bottom. Additionally there is a 30 foot stream with 3 water falls. At the top of the stream is a pit with lava rock as a bio filter. I use the test strips which do not test ph higher than 8.4 so I do not know how high it is, just that I am unable to get it below that. The same for alkalinity of 240 which I can not get any lower.

 

[Meyer Jordan]

Gypsum may or may not solve your problem.
What is the Hardness of the pond water?

 

[Lindasue]

And how exactly is that measured? Isn't "hardness" either ph or alkalinity?

 

[Meyer Jordan]

And how exactly is that measured? Isn't "hardness" either ph or alkalinity?

No. KH is Alkalinity, GH is Hardness, and pH is, or course, pH.
Are your fish having problems?

P.S. Beautiful pond!

 

[Lindasue]

No. KH is Alkalinity, GH is Hardness, and pH is, or course, pH.
Are your fish having problems?

P.S. Beautiful pond!

Thank you. It use to be a pool that we demoed.
My test strips do not test for GH. I think I need a better test kit. Suggestions?

 

[Meyer Jordan]

Test strips are typically not very accurate plus they do not have much of a shelf life.
I would suggest an API liquid test kit. There are two (2) different ones available but each is missing an important parameter test...either Nitrate or Phosphorous. Whichever test kit you choose you will also need to purchase the appropriate missing test.

 

[Smaug]

I have very hard Pa well water that definetly falls into the category of liquid limestone. I have a pH of over 8 usually and gh is always well over 200. It's been that way for over 10 years first with my little pond then with my big one. I also keep indoor tanks with the same water and one of them is a very successful amazon planted tank. In short,don't worry about ph,gh or kh unless you are at the low spectrum which is far worse.

 

[Lindasue]

Can gypsum be added to ponds? Most of my plants have died back and 2 fish have died.

 

[Smaug]

You say it was a pool you demoed? Does it have a rubber liner or is it cement? How big a pump do you have running? What is yiur nitrate,nitrite,ammonia readings?

 

[Meyer Jordan]

Gypsum can be safely added to ponds, but it is normally applied to clarify the water. It can be used to adjust pH, but certain parameters must be known to determine dosage and overall effectiveness, hence the need for accurate test results of pH, KH, and GH.
It is very unusual for the pH level in a Garden Pond to rise.