API Alkalinity test

shoelaceike · Dec 8, 2015

So I'm not big into testing....I usually test for nitrate and phosphate and thats it....once in a while I test calcium and alk and its always normal.....

Now that I've added a bunch of SPS, I decided to start dosing a bit so I tested my alk. My first test came to 20 dkh! My ph is 8.3 and calcium is 400.

Didn't make sense. I tested the tap water and it was about 6. I shook the bottle a bit and my last 2 tests were 9 and 10.....much better.....has this ever happened to anyone? What could have caused that crazy first test?

jason2459 · Dec 8, 2015

Settling. I always shake the bottles before use, drip a drop into a paper towel first, and drip with the bottle vertical and not slanted at all.

shoelaceike · Dec 8, 2015

Thanks..... I know on some they say to shake but not this one

Randy Holmes-Farley · Dec 8, 2015

FWIW, tap water can have a lot of alkalinity it it (sometimes more than a reef tank), so that's not the best counter test.

shoelaceike · Dec 8, 2015

Randy Holmes-Farley said:
FWIW, tap water can have a lot of alkalinity it it (sometimes more than a reef tank), so that's not the best counter test.

I only tested it as that is what I'm using now. I usually use ro so I had wanted to see if that was the cause.

Randy Holmes-Farley · Dec 8, 2015

shoelaceike said:
I only tested it as that is what I'm using now. I usually use ro so I had wanted to see if that was the cause.

If you use that tap water (6 dKH) to make salt water, the alkalinity of the new water will be very high.

shoelaceike · Dec 8, 2015

Randy Holmes-Farley said:
If you use that tap water (6 dKH) to make salt water, the alkalinity of the new water will be very high.

According to the last 2 tests it was 9-10. What is the dkh of ro?

Randy Holmes-Farley · Dec 8, 2015

shoelaceike said:
According to the last 2 tests it was 9-10. What is the dkh of ro?

RO/DI water has 0 dKH.

shoelaceike · Dec 8, 2015

Intersting.....I will double check the tap.

shoelaceike · Dec 8, 2015

So I checked all 3. As you said, the ro was 0. The tap was about 4-5 and the tank was 9. So it would seem that it was good that I used tap or the dkh in my tank would be 4-5, no?

Randy Holmes-Farley · Dec 8, 2015

shoelaceike said:
So I checked all 3. As you said, the ro was 0. The tap was about 4-5 and the tank was 9. So it would seem that it was good that I used tap or the dkh in my tank would be 4-5, no?

Salt mixes generally provide 7-13 dKH without any in the source water.

If the tank is low in alkalinity, tap water is not a good way to provide it since a lot of other stuff may come with it.

shoelaceike · Dec 8, 2015

Randy Holmes-Farley said:
Salt mixes generally provide 7-13 dKH without any in the source water.

If the tank is low in alkalinity, tap water is not a good way to provide it since a lot of other stuff may come with it.

I hear that. Thanks for the help....ai obviously need to dose alk