Question about pH

[ashirley]

Test results look good. KH is fine. Ph is OK and should be fairly stable. Please post the result of the pH test taken tonight so stability can be verified.
Is that Phosphate result 5 or 0.5 or 0.05? Which test kit are you using?
Do you know what the pond water temperature is?

 

[ashirley]

The test that just measures kh and gh. I will check it tonight along with the temp.

 

[Meyer Jordan]

FYI-Phosphorus levels
The EPA water quality criteria state that phosphates should not exceed .05 mg/l if streams discharge into lakes or reservoirs, .025 mg/l within a lake or reservoir, and .1 mg/l in streams or flowing waters not discharging into lakes or reservoirs to control algal growth (USEPA, 1986). Surface waters that are maintained at .01 to .03 mg/l of total phosphorus tend to remain uncontaminated by algal blooms.

 

[ashirley]

Pm test results ph=6.5 and phosphates still at 5ppm.

Should i be worried about that and if so how can i lower it?

 

[Meyer Jordan]

Keeping Phosphorus at <0.05 mg/L will greatly restrict algae growth especially string algae. Some Phosphorus is necessary for normal growth of all aquatic life, plant and animal so Zero levels are not wanted. Any commercially available Phosphorus binder will fill the bill. They are completely benign and the Phosphorus is permanently removed from the water column. PhosOut and PhosLoc are only two that come to mind. Follow directions per manufacturer.
It seems that we still may have a mystery on our hands. You reported that the pH this morning was 7.0 and now this evening it is 6.5. Ph levels typically increase during the day. Also based on your new test results a stable KH of 50 - 100 provides adequate buffering to prevent any pH crash.So the pH decrease was not a result of insufficient buffering.
I looked back through this entire thread and did not see any reference to any accumulated organic debris in the bottom of your pond. Is there any? How much?
I am going to need time to think about this A.M. to P.M. decrease in pH when it should have increased. There is still obviously some factor in play that has not been considered.
I don't normally request this but, if you would, repeat the same pH test tomorrow morning and evening and share the results.
We will resolve this mystery.

Edit Update: "If it had been a snake it would have bit me". That old saying certainly applies here. One major reason that your pH is testing 6.5 and 7.0 is your GH. This is bordering on the 'soft water' category. A level of at least 100 mg/L would be much better and will gradually increase the pH to a more mid-range reading.
The simplest way of raising the GH of water is with Calcium Chloride and Epsom Salts. This combination will keep ph swings to a minimum and the calcium and magnesium are good for your fish and plants. Start with 3 tablespoons of each dissolved in a container of pond water before adding it to the pond slowly pouring around the perimeter. Allow to mix and retest GH. Repeat this process until you achieve a reading of 100 - 150 mg/L'
Epsom Salt can be found most anywhere. Home Depot carries 'Pool Time calcium hardness increaser' which is safe for use around fish in the quantity required.
This may very well be the solution/answer to the "Mystery".

 

[crsublette]

@ashirley Thank you for your test results. Good to see your pH is stable at this moment. I would do this type of test again in Summer, when photosynthesis is more dominant, once your algae and microbiology seriously come alive.

As you mentioned before, you use well water for your pond.... I am quite curious what the phosphate level is of your well water. Share a quick phosphate test of your well water at the tap you use for your pond.

Are you using testing strips? ... that is... paper strips that you dip in the water... this will explain the difference in pH.

@ashirley At this moment, I believe your pH is stable. I believe your pH is most likely remaining 7.0 and this is due to your phosphate concentration. I ask you about the test strips since they are known to have a large variance test results.

There are two pH systems involved in water that concerns us... Phosphate and Carbonate... Most people have a carbonate pH system... Rare others that have dominant phosphate rock formations will have a phosphate pH system...

If you decide to do so, once you use those phosphorus binder chemicals... I would recommend you testing your pH and KH again a week after these binder chemicals are dosed.

 

[crsublette]

@ashirley .... @Meyer Jordan is correct, as I described before several posts ago, in that your pH should raise, not lower, by the time you do your dusk test. This is due to photosynthesis. Also, this and the fact you gave your KH and GH in a number range suggests to me you are using paper test strips... which is fine... but important for us to know. Due to your pH test results, my guess is that your KH is more likely closer to the higher range end of 100, which is perfect.

 

[crsublette]

@ashirley Let me reassure you in that there is NOTHING wrong with your pond's pH at this moment.... Good water for your fish... even with the phosphate level a little high.

Phosphate is high, as I expected, but I think this is typical of South Carolina ground well water due to the dominant rock formations in that area... This is why I ask you to share a Phosphate test from the well water tap you used for your pond.

If I think you are using API, then the phosphate test you are using actually goes up to 10ppm as well... There are good reasons for this that go beyond organic decomposition in the pond.

 

[crsublette]

@ashirley Also, my apologies for how useless the past 3 pages of this discussion thread may have been for you. Glad to see you did not give up on us.

 

[crsublette]

Sorry @ashirley ... this is just a post on the side... does not concern you.

Edit Update: "If it had been a snake it would have bit me". That old saying certainly applies here. One major reason that your pH is testing 6.5 and 7.0 is your GH. This is bordering on the 'soft water' category. A level of at least 100 mg/L would be much better and will gradually increase the pH to a more mid-range reading.
The simplest way of raising the GH of water is with Calcium Chloride and Epsom Salts. This combination will keep ph swings to a minimum and the calcium and magnesium are good for your fish and plants. Start with 3 tablespoons of each dissolved in a container of pond water before adding it to the pond slowly pouring around the perimeter. Allow to mix and retest GH. Repeat this process until you achieve a reading of 100 - 150 mg/L'
Epsom Salt can be found most anywhere. Home Depot carries 'Pool Time calcium hardness increaser' which is safe for use around fish in the quantity required.
This may very well be the solution/answer to the "Mystery".

@Meyer Jordan ... I have never heard of a lack of GH being the reason for a pH difference as described by @ashirley 's, that is a higher pH of 7.0 at dawn versus her lower pH of 6.5 at dusk....

...will be interesting to see how this process of increasing GH will actually normalize the pH in this manner... since the actual presence of Calcium Chloride and Magnesium Sulfate actually simply just dissolve in water, rather than actually reacting with the ions of water (to impact pH), thus Calcium Chloride and Epsom Salt should actually have a neutral (if not slightly acidic due to other variables) impact on already soft, acidic water. Actually, due to Magnesium's strong affinity to hydroxide in water, Magnesium Sulfate actually has a very slight acidic impact on water.

@Meyer Jordan ... if you have a simple hyperlink explaining your proposal here, then I would be very interested in reading it. ... you can send this in a private message to me if you feel more suitable to do... so that @ashirley 's thread does not go into another tangent.

If you would rather create a separate thread briefly talking about this, then this will be quite educational for everyone whom reads this forum.

Actually... this is an easy test I can do my self since I have a deionizing reverse osmosis filtration system... will be quite interesting...


Late Edit :: After some research... for anyone curious... dependent on how the Calcium Chloride product is produced, then this can contain calcium hydroxide impurities persuading an increase in pH, rather than a neutral reaction... Interesting stuff.. think I may wrote a thread about this.

 

[ashirley]

@ashirley .... @Meyer Jordan is correct, as I described before several posts ago, in that your pH should raise, not lower, by the time you do your dusk test. This is due to photosynthesis. Also, this and the fact you gave your KH and GH in a number range suggests to me you are using paper test strips... which is fine... but important for us to know. Due to your pH test results, my guess is that your KH is more likely closer to the higher range end of 100, which is perfect.

I am using the test with the test tubes and drops not strips.

 

[ashirley]

I will test the water in the tap after church. I do have some rocks that i found locally in my stream. Could the water coming into contact with these rocks increase the phosphate level? I am trying not to stress too much. We have a ton of frogs that could easily go live in the nearby creek if the water was too bad. The fish all look good. The pond does get a bit of shade late in the afternoon and it was late when i tested yesterday.

 

[crsublette]

I do have some rocks that i found locally in my stream. Could the water coming into contact with these rocks increase the phosphate level? I am trying not to stress too much. We have a ton of frogs that could easily go live in the nearby creek if the water was too bad. The fish all look good. The pond does get a bit of shade late in the afternoon and it was late when i tested yesterday.

@ashirley ... Yeah, those phosphate levels do not impact fish much, if any at all. The phosphate is mostly a concern that can possibly create some significant algae growth, which then the algae may create some fish health concerns if the algae gets incredibly thick.

I study aquaponics gardening as well. This involves fish actually swimming in far higher phosphate and nutrient levels as you have here and the fish are quite healthy. If you want to know more about what aquaponics is, then check out https://www.gardenpondforum.com/thr...n-a-commercial-scale.13572/page-2#post-218507.

 

[crsublette]

The test results are in.
GH IS 0 TO 50 PPM
kH is 50-100

I am using the test with the test tubes and drops not strips.

Interesting. Liquid test tube kits I am aware of do not have number ranges for their test results. The results are actually quite more specific dependent on the number of liquid drops used in the test tube.

@ashirley ... What is the name of the test kit you are using?

 

[crsublette]

Could the water coming into contact with these rocks increase the phosphate level?

Many things, including your fish's excrement, increase phosphate levels... I doubt your rocks alone would be the primary contributor to your high phosphate.

@ashirley ... Your high phosphate is due to one of 3 actions : 1) tremendous amount of organic decomposition in your pond; 2) your well water is high in phosphate; 3) not enough plant growth to consume those phosphates.

I think it is more of #2 and #3 because many of us water gardeners here have a tremendous amount of organic decomposition in our ponds, but rarely experience quite high phosphate levels.