Oyster shells.

[Lesley Gilks]

I tested the water yesterday and I'm pleased to say that Ammonia was nil, Nitrite was nil and Nitrate was nil. PH was normal but the K/H was 6 and G/H was 10 so would oyster shells be a good addition to the pond? Many thanks in advance.

 

[WaterGardener]

I use baking soda to raise the KH. It's quick and easy to use and works immediately.

Many use ground oyster shells, the type fed to chickens for calcium. Whole shells don't dissolve unless the water is in the acidic range, so I have to wonder how well the ground ones dissolve.

 

[GBBUDD]

@Lesley Gilks 6 as in 6 drops? that's perfectly expectable i believe that means your kh is 120 and is ok higher would be nice but if that's where your pond is naturally then i'd be happy

 

[j.w]

I tested the water yesterday and I'm pleased to say that Ammonia was nil, Nitrite was nil and Nitrate was nil. PH was normal but the K/H was 6 and G/H was 10 so would oyster shells be a good addition to the pond? Many thanks in advance.

I just asked that also but no one said anything on how it works or if it does.

Just found this comment by a person on an old pond forum:

Crushed oyster shells are used as a ph buffer. If the ph is low then crushed oyster shell should raise it (neutralize the acids) and then help keep it there. Acid in the water dissolves the calcium carbonate in the shells so if the water is not acidic the shells won't dissolve so it won't make it more alkaline.

Another person on an aquarium forum said this:
Some crushed coral/oyster shell (in a baggy in the tank) to increase KH too, as whilst bicarb and Epsom salts are instant for fresh water, the crushed shell works over a longer time period of course and gives (well in my tank certainly, an element of stability that I seemed to struggle with previously).

Whoa then I ran across our own forum talking about this in a long conversation way back when:
https://www.gardenpondforum.com/threads/poroxide-and-oyster-shells.9702/

OH BOY I'M ON A ROLL!

Here's a dude who did a test and put it on youtube:

 

[WaterGardener]

I wonder what kind of fish this guy has that live in water that acidic. Koi and goldfish would never survive in that.

Since oyster shells only dissolve in acid, there is no way the pH would ever get to anywhere near 8, no matter how much was used.

The pH never got out of the acidic range. That's the reason the oyster shells dissolved and raised the pH to a less acidic level. There is no way they could raise the pH to 8, no matter how much was used.

 

[j.w]

I wonder what kind of fish this guy has that live in water that acidic. Koi and goldfish would never survive in that.

Since oyster shells only dissolve in acid, there is no way the pH would ever get to anywhere near 8, no matter how much was used.

The pH never got out of the acidic range. That's the reason the oyster shells dissolved and raised the pH to a less acidic level. There is no way they could raise the pH to 8, no matter how much was used.

I don't think he has fish, just did the test to see what occurred.

 

[WaterGardener]

He mentioned fish in the video. Said they were swimming around fine. Or did I imagine that?

 

[GBBUDD]

I wonder what kind of fish this guy has that live in water that acidic. Koi and goldfish would never survive in that.

Since oyster shells only dissolve in acid, there is no way the pH would ever get to anywhere near 8, no matter how much was used.

The pH never got out of the acidic range. That's the reason the oyster shells dissolved and raised the pH to a less acidic level. There is no way they could raise the pH to 8, no matter how much was used.

Some Japanese koi breeders do use oyster shells to help with buffering but they also use a constant flow in their systems. They use a tall similar to a cistern where the water from a stream is dumped into the top and trickles over the oyster shells. But again it's a constant flow of NEW water.
You need a large amount of water and shells to do any real deteriorating to the shells.. my kh is low and I did add some chicken grit"oyster shells" has it worked I could not tell you but if it does add a fresh calcium carbonate to the pond even slowly I'll take it. Do I expect it to keep my kh at 180 nope not a chance

 

[j.w]

He mentioned fish in the video. Said they were swimming around fine. Or did I imagine that?

I prolly didn't pay that close of attention

 

[addy1]

My pond, first filled, ph 5.4. I didn't know, put in some Feeder fish, they died in less then a hour.

Then I found out our water is real acidic.

I left the pond empty for over a year, added about 200 lbs of shells to the bog let it run. Added plants to the bog, etcetera no fish. Our pH now sits about 7.6, the fish added lived.

I added shells for the next few years just in case. Have not added any in years now.

 

[Mmathis]

I followed @addy1 advice. (Old pond) my KH was 0. At least, for the few years following, KH was at least 100.

 

[j.w]

The shells are going in today unless the heat stops me! Gonna be darn 90 something today,grrrrrrrrrrr, too hot for here! If I don't hurry I won't be able to get my bicycle ride in either. Only 68 now but rising fast. I'll spend the rest of the day watering gardens by hand.