High PH level

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I just ran my first water test on my 3 month old pond. All tests ended up good except for the PH. It is running a solid 9.0. I know this is really high so what do I need to do now. Will baking soda neutralize and bring this PH down before something bad goes wrong.
Thanks
Bart
 

addy1

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I have read that baking soda will bring it down, why is so high? Do you have concrete in the pond, shells, wood?


from a fish forum

"Should you mess with the pH? In my opinion you are probably just as well off to leave it alone, even if it is high. You should check the buffering, AKA alkalinity, or sometimes called kh. It is probably high, but you should check it. If your buffering is between 100 and 400 you should not try to mess with the pH. If it is higher you could think about adding some acid, but watch the buffering closely, and don't pay too much attention to the pH. Usually people get into trouble by only watching the pH. It won't change much as you add acid, then all of a sudden after you have broken the buffer, the pH will crash and kill your fish. Pay attention to the kh!!!"

Baking soda is really the only product that should ever be used to drop the pH slowly and stabilize it. But like others have said, it is usually safer to just leave it alone, if it is stable.

A lot of times you'll get a high pH right out of the faucet from lack of CO2. Aerating it will drive more CO2 into the water, bringing the pH down.

Because of its chemical makeup, Baking Soda has unique capabilities as a Ph balancer or buffer. Buffering is the maintenance of a stable pH balance, or acid-alkali balance. As a buffer, Baking Soda tends to cause acid solutions to become more alkali and to cause alkali solutions to become more acid, bringing both solutions to a stable pH around 8.1 (slightly basic) on the pH scale. A buffer also resists pH change in a solution, in this case maintaining a pH of 8.1." The nature of baking soda is that it will give up H+ ions making more acids,
but only if the pH is above the buffer point. When it does this, it leaves behind carbonate ions, which could precipitate as calcium carbonate, (limestone), of calcium magnesium carbonate, (dolomite), if there is enough
carbonate and it is not being pushed back to bicarbonate. "
 
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What time of day did you test your pH? It tends to go up throughout the day. If your pH is stable from day to day and the fish are happy, I'd leave it alone.
 

addy1

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I had to add crushed oyster shells to get my ph to stabilize, our well water is in the 5-5.5 range. Since I added the shells (around 20-25 lbs 11k or gallons) I have not had an issue with ph, it is constantly the same. sitting right around 7
 
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This test was taken late last evening. So I will take another reading in the morning the first chance I get. Maybe Sunday morning.
Also the only concrete is a double layer of the those wall blocks that some of the big box stores sell. They are double stacked around the entire edge of the pond and also one cinder block on the bottom for raising up one of my plants.
I sure appreciate all the help I have received from this forum.
Thanks
Bart
 

fishin4cars

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were the cement blocks new? All those in conact with your pond water? If so your PH Could be maxed out. You have fish in the pond?
 
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Yes the blocks are in contact with the water and I have approx 100 goldfish ranging from 3" to 8" in size. The pond holds about 4800 gals.
 
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Good idea to test your tap/well water, but I bet its coming from the concrete. Did you cure it with a strong acid, rince it thoroughly?

edit: misread, thought the entire pond was concrete.

Either way, those blocks seem a very likely culpit. I was going to build a small wall with concrete blocks and cement, but I found no one or no product that could guarantee it would be fish safe without curing it, and since my pond is already stocked, I finally decided against it. Sounds like I made a good decission.

Anyway, what you could try is removing those blocks, and cure them with acid, and/or coat them with some epoxy paint.
 

fishin4cars

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Bart said:
Yes the blocks are in contact with the water and I have approx 100 goldfish ranging from 3" to 8" in size. The pond holds about 4800 gals.

How many come in contact with the water? I found that if you leave the concrete blocks out in the weather for a several months before using them they don't leach as bad. I can safely get away with four blocks in 2500 gallons with the PH only climbing about .2-.5 But I do use well weathered blocks, Never new ones for the pond. You can seal the blocks or acid wash and rinse them throughly. Even with that I would still soak and rinse them several times and then leave them in soaking water for a couple of days and see what the PH does in the rinse water, If it continues to climb you may have to repeat the whole procedure. Plastic milk crates or similar work far better and don't scrap the fish as bad as conrete blocks do for setting plants and such on.
Best way to lower the PH in the pond is water changes, and it's going to take a lot of water changing to lower it until the blocks are cured or sealed as they will continue to leach for a very long time.
 

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What about the red bricks they used to build houses with.........kinda look like terra cotta?
Would they change the ph also? I just put a few in my pond to raise up a pot :lol:
 
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I also had a reading of 8.5 to 9 and used Seachem's Acid Buffer figuring if it was good enough for aquariums then ponds should be no issue. I mixed it with a gallon of water and evenly dispersed it. I suggest using less than they say to be safe. About 1.5 fluid oz measure of the powder dropped my ~550 gallons by one whole number. I'm a little worried about the sudden change, but pH 9 can burn so probably worth the risk.
 
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j.w said:
What about the red bricks they used to build houses with.........kinda look like terra cotta?
Would they change the ph also? I just put a few in my pond to raise up a pot :lol:

Not sure about Ph, I suspect they are okay in that sense, but they will also not last for too many years when submerged. Probably not an issue if you only use them as "spacer" tho.
 
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I am now inclined to believe my PH problem is in the cement wall blocks I have installed around the edge of my pond. These blocks are the kind you find at Lowe's and Home Depot and other building stores for making low walls around flower gardens etc. They are about 12" long 7" wide and 4" thick and stack 2 high around my pond. There is 60 of them on the bottom row. The top row does not get under water. They were new and I did not know about neutralizing them before use. I have tested my well water and it is between 7.0 and 7.5 so I know that is not the problem so in the morning I will test my pond water again and see what I come up with there. If it is still high I think I will drop the water down below the bottom row of block. That way none of the cement blocks will be in the water and maybe the PH will drop down. If it does not I guess I will have to purchase something to bring it down.
 

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