Adding Alk without increasing PH with AFR and Bicarbonate

[Ziggy17]

If you want a higher alk, AFR will still generally work. It only adds 20 ppm of calcium for a 2.8 dKH alk boost, and the mag rise will be undetectable.

Perhaps there is an alternative explanation then. I used solely AFR to boost my alk from 7.9 up to 8.5. In doing so, my mag went from 1400 to 1550, my calcium went from 410 to 520. There’s always a margin for error in the trident testing but it can’t be that far off.

 

[Ziggy17]

There are just a few processes that consume alk and not calcium and magnesium in the exact ratios Miami gave. A sulfur denitrator is one, and rising nitrate is another. The most common ones are water changes with parameters that do not match the tank, and test error.

Would a 15% WC every two weeks throw off the numbers? I can only provide you what I’m seeing from the test results from the trident. If there are laws of chemistry that can’t be broken with Alk, Calc and mag consumption in a reef, then perhaps it’s the trident providing bad results.

 

[Randy Holmes-Farley]

In my experience AFR maintains my Alk at about 7 dKH, while Calcium is 450+ and MAG near 1400

I have to dose additional Alk to bring it to 8-9

AFR will maintain alk at other levels if you add more or less. There’s nothing special about 7 dKH except that you were adding an appropriate amount to offset demand at that alk level.

 

[Miami Reef]

I used solely AFR to boost my alk from 7.9 up to 8.5. In doing so, my mag went from 1400 to 1550, my calcium went from 410 to 520.

It’s impossible for AFR to do this.

 

[Randy Holmes-Farley]

Perhaps there is an alternative explanation then. I used solely AFR to boost my alk from 7.9 up to 8.5. In doing so, my mag went from 1400 to 1550, my calcium went from 410 to 520. There’s always a margin for error in the trident testing but it can’t be that far off.

Yes, test error. AFR does not contain that much magnesium or calcium.

For a 0.6 dKH alk rise, calcium will rise by 4 ppm, and magnesium less than 1 ppm.

 

[MrGisonni]

Use Balling Part B as needed to get your alk where you want it.

 

[Ziggy17]

Yes, test error. AFR does not contain that much magnesium or calcium.

For a 0.6 dKH alk rise, calcium will rise by 4 ppm, and magnesium less than 1 ppm.

Fair enough. Here are examples of trident test results from the same day. And the corresponding ICP test that day. Granted, this isn’t the example I gave earlier on with a high increase in Mag and Calc, but it does confirm increased mag and cal beyond what should be the norm. In this example, I was trying to elevate my Alk just above 9 dkh from 8.8 to see how if 9 Dkh was easily to maintain as that is still my target.

 

[Randy Holmes-Farley]

I’m confused. The icp magnesium and calcium values look normal?

The Apex values appear to be rising rapidly and are likely test error.

 

[Ziggy17]

Yep I’m confused as well. I know the trident isn’t a perfect test, but it seems like it’s fairly accurate based on ICP contrast. My Problem is that this scenario isn’t exactly uncommon for me. Which is why I stopped dosing AFR exclusively and started with Alkalin 8.3 P. But the rub with that is that it drives up PH into the 8.5 rang. So granted the premise of my question was inaccurate, it was based on my trident test results. Which seems to be accurate most times.
Aside from weekly ICP to determine actual results, what can I do to tighten up testing parameters? I’ve googled the lot number from the AFR ( 31324) to see if there was a “problem” but nothing comes up so I ruled that out as a culprit.

 

[Ziggy17]

Couple more recent examples.

 

[Randy Holmes-Farley]

I’d look into issues folks have with this device. If you dose nothing, magnesium should be perfectly stable and calcium should be nearly stable through 24 h.

 

[Ziggy17]

The noticeable upticks are when I dosed the AFR. Other than that, the cal and mag are relatively stable. Given the margin for error. But if AFR won’t do that, then that’s worrisome.

 

[Randy Holmes-Farley]

The noticeable upticks are when I dosed the AFR. Other than that, the cal and mag are relatively stable. Given the margin for error. But if AFR won’t do that, then that’s worrisome.

Did you dose it right by the place where the apex takes water? How often are samples actually taken? It looks like a smooth line, but obviously it isn’t.

 

[Ziggy17]

Did you dose it right by the place where the apex takes water? How often are samples actually taken? It looks like a smooth line, but obviously it isn’t.

I hand dose in the DT with flow on. The test samples are taken from the Skimmer compartment in the sump. That’s also where I keep the probes aside from the temp probe which sits in the return compartment. ALK is sampled 4x/day cal/mag 2x/day.

 

[Ziggy17]

Here is a typical 24 comp taken yesterday and today. About .2 Dkh decrease, no cal decrease and 5 ppm mag decrease.