Alk too high

[Almondsaz]

I just tested my reef tank and got the following results:

PH 7.9
Salt 1.025
ORP 453
Phos 0
Calcium 440
Amonia 0
Nitrite 0
Nitrate 40

My big concern is the alkalinity. My PH has been low (and I did the test the water inside/outside to see if it is room CO2 and it wasn't) so I have been using part B of the Kent Marine 2 part buffer system to work on the PH.

2 weeks ago the calcium had been 560, so now I would say it is in the normal range.

Nitrates are too high, but I am doing a water change tomorrow and that should take care of the Nitrates.

What do I do about the alk, never had it that high?

Thanks for helping!

[Percula9]

You didn't list the alkalinity in your water parameter list.

[Almondsaz]

It is 14.4 dKH via a Salifert Test Kit.

[bertoni]

Using the buffer to fix the pH problem is going to cause this problem. I would get a second opinion on the pH test kit, since there's not much that can lower pH except for CO₂. pH at 7.9 isn't that bad, especially if that test was made in the morning.

[Almondsaz]

My PH is via a probe that was just calibrated a couple of weeks ago. The probe is part of my Aquacontroller III. I will hold-off on any more buffer.

[bertoni]

Limewater can help with low pH problems.

How long was the water sample aerated outside?

[Almondsaz]

not more than 1/2 hour

[bertoni]

It takes a few hours to reach equilibrium. I think the tank should be fine if the daily low pH is 7.9.

[Almondsaz]

The daily low can go down to 7.8 and up to 7.96

[bertoni]

I don't think that's all that bad. Some limewater might help, if you're worried.

[stevensun]

Is Kalkwasser an alternative for limewater? Will adding limewater increase the KH?

[tmz]

Kalkwasser is the German name for limewater and used more often in hobby products. Limewater(calcium hydroxide) is a balanced supplement. It adds both calcium and alkalinity in balnced proportions. If you just wan't to raise alkalinity the alkalinity portion of any two part product will sork.

[Billybeau1]

Yes limewater will raise kh, pH and calcium slightly.

If you want to just raise kh, good old Arm & hammer baking soda will do. If you want to raise kh and pH, baked baking soda will do the trick.

The original poster already has high kh due to using pH buffers. This is never a good idea long term.

In the winter time when houses are closed up, a pH reading of 7.8 to 7.9 is certainly acceptable and should not be a cause of concern.