Why is my Alk soooo high?!

gemini aquarius(t)

Always Learning
Sooooo.. I've been doing this aquarium thing for a while now... like 9 years and I have never seen anything like this before.

With my most recent tank, a 2.5 gallon I have had ridiculously high alkalinity. Like RIDICULOUSLY high. the first time I tested alkalinity it tested at 12 or 14... not positive. This time I tested it was at 16.8!!!!! WHAT THE HECK?! After each testing session I double checked with other tank water that checked out and confirmed that it was calibrated. The first time I had also checked salinity and it was 1.028 so I added fresh water and have been doing large-scale water changes, as is recommended in pico systems, and replacing carbon regularly. This time I tested calcium and it read BELOW 200!! Unreadable! I have had pretty bad water quality throughout the years, but nothing like this.

I dont dose anything, and water is changed on average once a week.

in between these tests, I thought the extra pump may be increasing the water temperature and altering elements or altering test results, so I turned it off.
I also removed the crushed coral, thinking it may be buffering the tank as water flowed over it. I also thought the detritus being trapped in the gravel, which was fairly significant, could just be deteriorating conditions in general.
Also between tests I turned the lights to a lower percentage in case the leds were somehow drawing something to go array in the chemistry.. (Yes, I know it sounds crazy, but I'm running out of ideas)
Other notable info is that the "control" water was tested between 8.1-8.5 the two times and that I have done a total of 500% water change since the first test.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
I expect a testing error more than anything else, despite your assurance that isn't the case. :D

Crushed coral cannot be boosting alkalinity and not calcium, no matter what you do to it.

What salt are you using and have you measured alk and calcium in it?

Are you using tap water?

No additives of any kind?
 

bertoni

Premium Member
I agree that testing error is a common problem. pH buffers might be capable of driving the alkalinity to 16.8 dKH.
 

gemini aquarius(t)

Always Learning
I expect a testing error more than anything else, despite your assurance that isn't the case. :D

Crushed coral cannot be boosting alkalinity and not calcium, no matter what you do to it.

What salt are you using and have you measured alk and calcium in it?

Are you using tap water?

No additives of any kind?
I hope it is testing error, although I have tested the water straight from where I get it, and then immediately tested the water from my tank, and the tests showed the same. Water is NSW from here in Miami, and I have never put tap water in the tank.
No additives either, only large (a gallon and a half) water changes.

I agree that testing error is a common problem. pH buffers might be capable of driving the alkalinity to 16.8 dKH.
I have not added anything to the tank such as pH buffers.
 

gemini aquarius(t)

Always Learning
Just redid the tests after changing tanks, and starting over with new rocks. Alk started at 8.0 the day after setting it up, and now, about a week later, and after last nights water change, alkalinity is at 9.9 again and calcium is 462. Magnesium is 1215.

Salinity is a little high at 1.027 so that may have an effect?
Im reaching for straws here.
 

dartier

New member
You mention you changed your rocks, are they natural or a man made or a cultured substitute? Just in case they are not natural and are leaching alkalinity like some of the cement based rocks are known to do until they are sufficiently cured.

Dennis
 

gemini aquarius(t)

Always Learning
You mention you changed your rocks, are they natural or a man made or a cultured substitute? Just in case they are not natural and are leaching alkalinity like some of the cement based rocks are known to do until they are sufficiently cured.

Dennis

In the old tank there were two small pieces of Real Reef rock which is manmade, I left them out of this new tank, and there are only pieces of live rock that have been in an established system for at least 8 months.

I did test again today after adding 1.5mL of calcium
and the results were
Ph 7.6 (low)
Alk 10.9 (a full point higher than the last test)
Calcium 504 (42 points higher than the last test which makes sense after dosing)

Now I'm really lost. What can cause alk to shoot up this quickly overnight and even after dosing calcium?!
 

Randy Holmes-Farley

Reef Chemist
Premium Member
I agree that man made rock can do it, but otherwise, not much can oost alkalinity on it own.

What are you dosng for calcium?

What are you using for top off?

Is the water clear that that there's no chance CaCO3 particulates are getting into the test?
 

gemini aquarius(t)

Always Learning
I agree that man made rock can do it, but otherwise, not much can oost alkalinity on it own.

What are you dosng for calcium?

What are you using for top off?

Is the water clear that that there's no chance CaCO3 particulates are getting into the test?

That rock was the only thing I could think of because I didn't dose ANYTHING before yesterday and that was 1.5 mL of Natureef calcium. Top off I have been using Nestle pure life drinking water. Tested for alkalinity in there and it was close to 0 i think it was .1 or something nominal.


water is always clear when I test.
 

oldsaint

Just me
Premium Member

gemini aquarius(t)

Always Learning
If I'm reading it right, their own water analysis shows a 14-34 ppm of bicarb. Plus, various other minerals and metals. Not sure if this has anything to do with your problem but personally I would find another source of water.

http://www.nestle-watersna.com/asset-library/documents/pl_eng.pdf

HMMMMMMMM. Very interesting. Thanks for looking that up! I wouldn't have thought of looking for the actual reported test results. I will definitely check that out, and change my top off water.

I was talking with a friend and the only other guess he had was that it could be leaching from the frag plugs. Not sure, but may be worth a shot to chip all the frags off.
 

TylerHaworth

New member
Wouldn't 1.027-1.028 be causing the higher alkalinity?

Are you topping off with RO/DI every day or just doing your water change once per week and just refilling with saltwater?

Edit: went through thread a little better... Bottled water definitely has baking soda in it... I think the elevated salinity + bicarb in the bottled water, once addressed, will help
 

gemini aquarius(t)

Always Learning
Wouldn't 1.027-1.028 be causing the higher alkalinity?

Are you topping off with RO/DI every day or just doing your water change once per week and just refilling with saltwater?

Edit: went through thread a little better... Bottled water definitely has baking soda in it... I think the elevated salinity + bicarb in the bottled water, once addressed, will help

I'd switch to RO/DI or distilled for a bit before removing frags. :)
Topped off with a liter of RODI and this morning alk was down to 10.0

I will take it.

Compared to NSW at 35 ppt (sg = 1.0264) with 7 dKH, a salinity of 1.028 NSW will have an alkalinity of 7.4 dKH. :)

Wow, didn't know salinity played such a major role in alk levels. Learn something new every day. Thank you for the time and help. I will update in a week or so unless something crazy happens
 
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