Syn-Biotic Salt Parameters

[Pêcheur]

I’ve been battling low pH, 7.6 - 7.77 since I set up my tank in early May. I’ve been dozing soda ash to try and bring it up but it’s never reached 7.8 and always falls back to the aforementioned range.

I noticed in last weeks water change that it dropped immediately after to 7.6.

I just made a batch 2 hours ago and used my probe to measure the pH at 8.07. I then did 3 Hanna colorimeter Alk tests and the Alk was 6.8, 7.0, 6.8.

Do the organics in this mix compromise these Alk tests? I thought it was supposed to be in the 8-9dkh range?
My salinity is 1.024 @ 77F measured with an optical refractomer.

 

[Shirak]

1.024 salinity is on the low side. If you increase to 1.026 range it will also increase Alk. You might also have higher and more stable pH from the more concentrated carbonate ions.

I’ve been battling low pH, 7.6 - 7.77 since I set up my tank in early May. I’ve been dozing soda ash to try and bring it up but it’s never reached 7.8 and always falls back to the aforementioned range.

I noticed in last weeks water change that it dropped immediately after to 7.6.

I just made a batch 2 hours ago and used my probe to measure the pH at 8.07. I then did 3 Hanna colorimeter Alk tests and the Alk was 6.8, 7.0, 6.8.

Do the organics in this mix compromise these Alk tests? I thought it was supposed to be in the 8-9dkh range?
My salinity is 1.024 @ 77F measured with an optical refractomer.

 

[Pêcheur]

1.024 salinity is on the low side. If you increase to 1.026 range it will also increase Alk. You might also have higher and more stable pH from the more concentrated carbonate ions.

Can you provide more details about concentrated carbonate ions you referred to?

 

[Shirak]

Can you provide more details about concentrated carbonate ions you referred to?

Well what I mean is, since your salinity is low, everything is low including alkalinity. By increasing your salinity you will increase alkalinity and the water will have more buffering capacity to handle dissolved CO2 and lower pH

 

[Pêcheur]

Well what I mean is, since your salinity is low, everything is low including alkalinity. By increasing your salinity you will increase alkalinity and the water will have more buffering capacity to handle dissolved CO2 and lower pH

That makes sense, but I do usually mix to 1.025. I stopped today as to drop the tank salinity a bit as it was 1.027. Does that little bit of salinity difference really impact Alk/pH that much?

So it seems my pH problems were attributed to a poorly calibrated probe. I purchased new calibration fluid and the 7.0 fluid was reading 6.7.

I recalibrated and the fluid pouches are now reading 6.97 & 10.00 and my tank pH climbed to 8.06

 

[Shirak]

That makes sense, but I do usually mix to 1.025. I stopped today as to drop the tank salinity a bit as it was 1.027. Does that little bit of salinity difference really impact Alk/pH that much?

So it seems my pH problems were attributed to a poorly calibrated probe. I purchased new calibration fluid and the 7.0 fluid was reading 6.7.

I recalibrated and the fluid pouches are now reading 6.97 & 10.00 and my tank pH climbed to 8.06

Nice!
Regarding the salinity it could explain why your salt is mixing to 7dkh when it should be around 8-9.

I think Randy mentioned once that going up a couple points in SG could make roughly a .5dkh difference. He would be better able to answer your questions. It may even show on the bucket the range you should be seeing based on your salinity. What are you testing Alk with? Could be some testing differences also.

 

[Mhart032]

I used this salt and i get pretty steady readings at 35ppt or 1.0264 when i mix.

PH 8.35ish
ALK 8.10ish ( i buffer this down to 7.6ish to match my tank)
CAL 4.80ish
MG 1320ish

 

[Pêcheur]

Nice!
Regarding the salinity it could explain why your salt is mixing to 7dkh when it should be around 8-9.

I think Randy mentioned once that going up a couple points in SG could make roughly a .5dkh difference. He would be better able to answer your questions. It may even show on the bucket the range you should be seeing based on your salinity. What are you testing Alk with? Could be some testing differences also.

I use the Hanna colorimetric Alkalinity tester

 

[Hans-Werner]

I then did 3 Hanna colorimeter Alk tests and the Alk was 6.8, 7.0, 6.8.

The Hanna colorimetric Alk test must work different from "normal" titrimetric Alk tests. Maybe this makes a difference. We will check this.

 

[Pêcheur]

The Hanna colorimetric Alk test must work different from "normal" titrimetric Alk tests. Maybe this makes a difference. We will check this.

Hi and thanks. Please let me know if this affects the results you get. I wondered if the organics in the mix mentioned to affect conductivity readings were affecting the colorimeter test. Those test results I got were not reasonable to me, which is why I tested 3 times.

With my probe being calibrated correctly My tank parameters seem to be reading pH around 7.92 -8.02, my tank ALK reading 24 hours after a water change read 7.5.

 

[Hans-Werner]

I have just spoken with our lab technician. She says, usually with the Hanna checker we get a bit lower results than with our test kit which is made with acid of defined concentration for titration. She will check once more especially for Syn-Biotic the next time we make a batch of Syn-Biotic.

I guess the lower results with the Hanna Checker (see also tolerance of this test) together with the low salinity might sum up to maybe 1 dKH.