Very weird Alk Numbers

[glb]

My Alk has been creeping due to a dosing error (gradually over several weeks). It normally sat at about 10.5 went to 11.8. On 8/11 I turned off the dosing pump to let it fall. The following week, 8/18, with no dosing, the Alk was 12. I had to replace my Hanna reagent so I thought that was it or a testing error. I retested using Salifert and got 11.8. Today, I tested the Alk again. Hanna was 11.7 and Salifert is 11.4. I have one acan colony which is growing like crazy (first coral and added it 2 weeks ago). What I can’t figure out is why it’s not dropping more quickly. Even before I got corals I dosed 1.4ml daily to maintain an Alk of 10.5. Ca is 490. I haven’t tested Mg today but last week it was 1365. My Ph fell a little (8.1 to 7.95) so I thought Alk must’ve dropped more than it did. I change 5g every two weeks, which in the past didn’t change the Alk. I went a month without a water change and that’s when the Alk went up. To me these numbers make no sense. Does anyone have any idea what might be going on? Everything in the tank is fine but I’m working on stability so I can add more corals.

 

[redfishbluefish]

You have one coral! Sit back, relax, have an adult beverage (assuming you're of age ), and stare at your tank....and let both alk and calc drop without dosing. Measure every day or two until your numbers get to where you want them. Also, what salt are you using....if it's what I call, one of the "super" salts, that could be boosting your alk (and calc) numbers.

 

[glb]

You have one coral! Sit back, relax, have an adult beverage (assuming you're of age ), and stare at your tank....and let both alk and calc drop without dosing. Measure every day or two until your numbers get to where you want them. Also, what salt are you using....if it's what I call, one of the "super" salts, that could be boosting your alk (and calc) numbers.

I’m using regular Instant Ocean. I know nothing’s wrong, but the Alk was lower before. I just added T5 lights. Can that affect Alk? I think I will now have a glass of wine and count acan polyps.

 

[chipmunkofdoom2]

The alkalinity likely did not rise. The rise you observed is probably a result of the small inaccuracy inherent in hobbyist test kits. I'm not aware of any mechanism that can cause your alkalinity to rise without adding bicarbonate or carbonate (or boron). Unless, of course, your pH is so low that coral skeletons and rock start dissolving (< 7.5 - 7.6).

It's worth keeping in mind that plain Instant Ocean has relatively high alkalinity (10 - 11 dKh). So if your goal is to keep alkalinity below 11 dKh, water changes will likely actually increase your alkalinity.

 

[glb]

The alkalinity likely did not rise. The rise you observed is probably a result of the small inaccuracy inherent in hobbyist test kits. I'm not aware of any mechanism that can cause your alkalinity to rise without adding bicarbonate or carbonate (or boron). Unless, of course, your pH is so low that coral skeletons and rock start dissolving (< 7.5 - 7.6).

It's worth keeping in mind that plain Instant Ocean has relatively high alkalinity (10 - 11 dKh). So if your goal is to keep alkalinity below 11 dKh, water changes will likely actually increase your alkalinity.

Thanks. Ph is between 7.9 and 8.1 so it’s normal. Adding the T5’s helped with ph. I may add an algae reactor to stabilize it. I know I don’t need to worry about any of this now, but I’m trying to learn good habits now before I get more coral.