I tested my water the other day -- first time for the season. I have my numbers for this test as I write this, but am relying on memory for the results of previous tests (I have the info, just not in-hand at the moment).
Ammonia -- 0
Nitrites & nitrates both -- 0
pH -- 7.8
KH -- 72
GH -- 107
2) While this pH is a good number, it's slightly lower than usual -- it usually runs around 8-ish, 8.2....
The KH is about the same, maybe a tad lower than past readings, and I know that ideally you want the KH to be above 80, and preferably in the 100's.
3) About 2 weeks ago I changed out my crushed oyster shells. I keep them in a mesh bag, inside my SKIPPY, where they are in the direct flow of the water.
4) Should I be concerned at this point, or just continue to monitor? Should I UP the amount of oyster shells? And, if I add baking soda, how much do I add?
1) BTW, found this article that does a good job of explaining the relationship between pH & KH, and the importance of consistency and making slow, gradual changes....
http://www.jnfkoifarms.com/basicwaterquality/morebasicwaterquality.html
4) Should I be concerned at this point, or just continue to monitor? Should I UP the amount of oyster shells? And, if I add baking soda, how much do I add?
Meh, you're on the edge between being concerned or not, that is justifiably right to be paranoid.
Personally, I would significantly increase the volume of oyster shells in addition to adding baking soda, which the directions and reasons why are expressed below.
However, for your 3rd question, I would need to know your pond's total volumes of water in gallons and this needs to be an accurate guess, or as close to it as possible.
1) BTW, found this article that does a good job of explaining the relationship between pH & KH, and the importance of consistency and making slow, gradual changes....
http://www.jnfkoifarms.com/basicwaterquality/morebasicwaterquality.html
Yep, Mr. Fornaro does a good job in that article and overall website and is an honest pond consultant. He is also mentioned in another thread,
i really wish I had these when i started.
Once the KH is at 7dKH (or 125ppm), then the water's pH will always be at around 8.3~8.5. You can push the KH up to 16 dKH, which is what my source water actually is, and the pH would still be around 8.3~8.5. If the pH is ever higher than this, then this means the water has, in relative relationship to the KH volume, a lower volume of
free calcium in the water.
3) About 2 weeks ago I changed out my crushed oyster shells. I keep them in a mesh bag, inside my SKIPPY, where they are in the direct flow of the water.
No reason to change it out since the product is not an absorbent. Now, it might need to be cleaned a little by simply spraying water over it. It is just that, when the pH gets closer to 8.2, then the product's dissolve rate into water significantly decreases and stops dissolving at 8.2 pH. However, again, as the pH drops momentarily, then more of it dissolves. This is why significantly more of the product must be use when a pond's pH is above around 7.3~7.5.
2) While this pH is a good number, it's slightly lower than usual -- it usually runs around 8-ish, 8.2....
Did you test the water earlier in the day than you usually do? Due to your KH being at 72 ppm, then this would explain why the pH is 7.8 rather then around 8.0~8.2ish. This variance is quite likely broader than you realize, that is especially true after a heavy rain storm.
Personally, I would slowly increase the KH to 7dKH (or 125ppm) so there would not be this pH variance throughout the day. The water is dosed
slowly by only changing the water KH in 1dKH (or 17.898 ppm) increments over a 24 hour period with typical grocery store, no additives, pure food grade baking soda, that is sodium bicarbonate. The
slow dosage is to reduce the stress on the fish since fast changes in alkalinity can make them sick. You can determine the dosage amount from the
CNYKOI - Alkalinity (KH) calculator. This product equilibriates, or dissolves, quite fast into water
but it is still not instantaneous and takes time to dissolve. Personally, I would first add the predetermined dosage amount, that is dependent on your pond's total gallon volume, to be mixed in a 5 gallon bucket of water and add a small aquarium air stone to this to speed up the equilibriation process; then, after 12 hours, add this solution around the parameter of your pond or in an area of fast moving water such as a stream. Now, after the pond is dosed, wait 24 hours before using the KH test kit to test the water's alkalinity. Then, if you need to increase the KH more, then repeat the aforementioned process.
This could take a period of days to properly adjust, which is quite fine since it takes into consideration the safety of the fish.
However, there is one disadvantage to using pure food grade baking soda, that is sodium bicarbonate, and this disadvantage is the "sodium" component. It takes a
long time, that is over a period of a year or so, for this product to increase your pond's salinity quite slightly, that is only 0.05~0.10%. So, if you are heavily relying on this product for alkalinity, then I would do a
slow major water change, that is of at least 40%, once or twice a year so to prevent this product from increasing the pond's salinity. Also, this salinity is a
different type of salinity when compared to a salinity caused by the accumulation of chloride ions to defend against nitrite poisoning.
This is also why I encourage the use calcium carbonate products even though this product essentially stops dissolving when the pH reaches 8.2 or higher; however, if at any moment the pH were to drop below 8.2, then the product would slowly dissolve into the water. Also, the beneficial bacteria that forms around this product in the water will be given a boost to water filtering as well. There never can be too much of this calcium carbonate product in the pond and I would also strongly encourage using it as a mix, along with
laterite clay, in with the pond plant pots and to do a quite heavy layer of it on the bottom of streams and heavy quantities of it in bogs.
Now, instead of baking soda, then you can use
Potassium Bicarbonate, which is most often bought online. I could not find any calculator on how to properly determine the dosage volume, but this product is used quite heavily in the aqua-ponic gardening hobby. The aqua-ponic hobby is the result of a collision of interests that involve safely growing fish, even including typical goldfish, and safely growing plants. If this is an interest to you, then check out the thread,
is aquaponic farming truly viable?, which I will be doing another update on it here soon.
Potassium Bicarbonate is significantly more expensive than baking soda, but, with this product, you avoid the salinity concerns and also add a nutritional boost to your aquatic plants. Although, there is the potential of this boosting algae growth as well. So, you could go half and half, that is still use baking soda except use less baking soda due to using some Potassium Bicarbonate.
Personally, I would approach the same dosing instructions with Potassium Bicarbonate as I would with baking soda. However, you will have to do a "wait & dose & see" method with Potassium Bicarbonate, in a 5 gallon bucket, so you can determine exactly how much you need so that you do not increase the alkalinity too fast in your pond.
In aquaponics, there is actually a constant flow through drip system that operates much like a medical-IV, that is built much like a venturi, injection into the water to maintain the alkalinity in their systems, which in their systems they try to work with an alkalinity of around 1~2dKH while controlling the pH fluctuations. However, there needs to be multiple safeguards in place with this system to ensure "accidents" do not greatly increase the water's alkalinity too fast.
