One tank has lower ph

[Pudge&Bubbl]

Out of 4 tanks- one has lower ph. They all are set up with the same water mix, all in the same area, all within 74-78* .....

But one has lower ph. Tested all at the same time today- re-tested that tank again because it didnt make sense.

I just set up a 120 gallon this past week, but decided to move all tank to one room. So... I moved the 36 bowfront, the 20-QT and the 10-former-QT to that room, using some fresh saltwater to help with the moving of everything around.

Everything only had added saltwater. The ph of that tank was the same as the others until this morning.

Ideas of other things I can check that affect ph?

 

[Randy Holmes-Farley Verified Community Expert]

How are you measuring the pH? For such an experiment, it is best to measure pH in a cup away from any of the tanks, using the same pH meter one after the other.

Aside from small effects of temperature and salinity, pH is determined mathematically by the carbonate alkalinity and the level of carbon dioxide in the water. Everything else being the same, a tank with twice the alkalinity will have a pH value about 0.3 pH units higher than the tank with the lower alkalinity.

 

[Pudge&Bubbl]

How are you measuring the pH? For such an experiment, it is best to measure pH in a cup away from any of the tanks, using the same pH meter one after the other.

Aside from small effects of temperature and salinity, pH is determined mathematically by the carbonate alkalinity and the level of carbon dioxide in the water. Everything else being the same, a tank with twice the alkalinity will have a pH value about 0.3 pH units higher than the tank with the lower alkalinity.

I use API for ph. I have a test tube rack with 30 or so test tubes. I took sample water from all 4 tanks, distributed through assigned rows, and proceeded to add the reagents through each row. I use API for ph, ammonia, nitrites, nitrates. Hanna for alkalinity and phosphate. Salifert for magnesium. And aquaforest (?) For calcium. Just happens to be my collection at the moment.

I do this at my kitchen table. When I noticed the difference, I immediately re-tested with a new sample and tube, to rule out that I may have miscounted my drops. This tank came out at 7.8 , whereas the other three came out at 8.0/8.2. I know that's not a huge difference, but I just dont understand yet what can cause the difference.

I also noticed last night that the water is also a little cloudy.

Calcium was low, but magnesium a tad higher than recommended, and alkalinity normal.

I'm still learning all of these relationships. I was surprised calcium was so low, because my salt mix is usually pretty spot on. And I thought that if calcium is being used, the others go down as well?

Ph was 7.8
Calcium was 240
Magnesium was at 1500
Alkalinity was 9.5

What is the easiest way to bring calcium back up without adding to the rest?

 

[Randy Holmes-Farley Verified Community Expert]

And I thought that if calcium is being used, the others go down as well?

Ph was 7.8
Calcium was 240
Magnesium was at 1500
Alkalinity was 9.5

What is the easiest way to bring calcium back up without adding to the rest?

Dose calcium chloride.

The calcium is not being used if alkalinity is not declining.

Don't try to interpret small test differences, especially a test like the API pH.

 

[VKP01]

Did you test ammonia? It can lower pH. If it has less aeration/surface agitation than the others that could affect it as well.

The easiest way to bring your calcium up would be with a 2 or 3 part dosing system that would allow you to dose each element individually. If your salt has values you want, then you could just do a water change.

 

[Pudge&Bubbl]

Dose calcium chloride.

The calcium is not being used if alkalinity is not declining.

Don't try to interpret small test differences, especially a test like the API pH.

If calcium is not being used, where did it go? Now that every tank has been moved, I am going to be testing regularly again. This past week got away from me.

 

[Randy Holmes-Farley Verified Community Expert]

Did you test ammonia? It can lower pH. If it has less aeration/surface agitation than the others that could affect it as well.

The easiest way to bring your calcium up would be with a 2 or 3 part dosing system that would allow you to dose each element individually. If your salt has values you want, then you could just do a water change.

Ammonia production lowers pH by lowering carbonate alkalinity. So measuring alkalinity is adequate. There is no other chemical effect on pH except carbonate alkalinity and carbon dioxide.

 

[Randy Holmes-Farley Verified Community Expert]

If calcium is not being used, where did it go? Now that every tank has been moved, I am going to be testing regularly again. This past week got away from me.

Test error, was never there, you added alk some other way, salinity is low, etc.

 

[Pudge&Bubbl]

Did you test ammonia? It can lower pH. If it has less aeration/surface agitation than the others that could affect it as well.

The easiest way to bring your calcium up would be with a 2 or 3 part dosing system that would allow you to dose each element individually. If your salt has values you want, then you could just do a water change.

Ammonia was undetectable. Surface is moving quite beautifully. And around 10-15 gallons out of the 20 was new saltwater.