Puzzled why Alk is going up

Maximus · #1 12/30/2007, 05:55 PM

Well, this is a new one for me. I've been testing my alk for the past week and it's been hovering around 10-12 dkh. Why is this strange? It's strange because I haven't been dosing anything and my calcium reactor is not even on. Any ideas? Btw, I added around 20 acro frags a few days ago and hoped to see the alk go down. Funny thing is it keeps going up. I tested the alk a few days ago and it was around 10 dkh. It is now at 12 dkh. I am totally confused by this. Btw, I am using the Lamotte Alk kit and have double tested each time with the same results. Any ideas?

Percula9 · #2 12/30/2007, 06:00 PM

Try an API test kit to see if it confirms the Lamotte results. 12dkh is still within normal limits, though the upper limit. Have you done any water changes? If so what brand of salt? What is the pH ?

Maximus · #3 12/30/2007, 06:07 PM

I havent done a water change for a couple weeks. The ph ranges from 7.9-8.25. I use IO salt. I just cant understand why the alk goes up when I have not dosed anything to the tank.

bertoni · #4 12/30/2007, 07:01 PM

That's strange. Is there any DIY live rock in the tank?

Maximus · #5 12/30/2007, 07:53 PM

No diy live rock at all. My ph has been fairly high so no chance of it dissolving the rock. Perhaps IO is naturally high in calcium/alk? However, this would not lead to the alk increasing.

bertoni · #6 12/30/2007, 10:12 PM

The most common causes of high alkalinity are DIY rock and the use of pH buffers. Something's going into the system, or the test kit is going crazy. Have you tested the topoff water?

Maximus · #7 12/30/2007, 10:50 PM

Good idea. I will test the rodi water and report back. Thanks.

stevensun · #8 12/31/2007, 12:31 AM

I would suggest testing the RODI water too. I used to buy mixed salt water from a LFS. My KH kept going up and bothered me for a while. One day I somehow tested the KH of the salt water from the LFS; it was 16 dKH....according to their inspection, it was their RO filter.

Maximus · #9 12/31/2007, 12:52 AM

Ok, something wacko just happened when I tested the rodi water. I basically used one drop of the alk fluid and it changed to the desired color. This cannot be right.

bertoni · #10 12/31/2007, 01:20 AM

Does that indicate zero alkalinity with your test kit? If so, that's good news, at least for the RO filter.

Maximus · #11 12/31/2007, 01:32 AM

Yes, it would indicate near zero alk. So, rodi water is supposed to read 0 alk?

bertoni · #12 12/31/2007, 02:21 AM

Yes, it should read zero. So the filter is not the source of the alkalinity.