Alk sustaining high levels without dosing

[argiBK]

I’m transitioning from All for Reef to BRS’ hybrid balling method, as of today, it’s been about three weeks since I’ve stopped dosing AFR. I also monitor my dKH with KH Keeper Plus since starting the transition.

Admittedly, I infrequently tested alk prior to this shift as AFR seemed dialed in. My alk levels have maintained relatively high levels between 10.4 - 10.9 (KH Keeper and Hanna) without any dosing. Calcium consumption seems to be normal (415, ~15ppm/day, Hanna). Magnesium levels hover around 1300 (Salifert). I am dosing the Calcium Carbonate part of the balling method, and manage Mag via weekly water changes.

I’m sort of at a loss as to what’s happening, and I’m waiting for dKH to drop to 8.5 before I start dosing for alk. Could the AFR still be in the system after all this time?

 

[KrisReef]

Seems like it is?

 

[Randy Holmes-Farley]

I don't think after 3 weeks, its remaining an alk source.

Are you dosing nitrate or is it declining?

Alk consumption in your tank ought to be about 2.2 dKH per day, if the calcium dosing is correct. That is a pretty large daily dose of AFR to have supplied that much.

Have you double checked that you are correctly dosing the calcium part and not the alk part? You certain the calcium dosing line is delivering the amount it is supposed to?

 

[silvia_10]

Hi, i’m transitioning from Triton to AFR and have the same problem.

I have a 240l reef tank with a 60l sump, with SPS and LPS corals that with the Triton method have worked very well for 3 years.

Three weeks ago I decided to switch to AFR and started with the manufacturer's recommended dosage. Overnight, the Alk rose from 8.5 to 10.3 and from there it hasn't gone down. I have reduced the dose from 12ml to 8ml and 4ml per day, and there is no way to lower the alkalinity, it is still at a very high level. It should be noted that I measure every day at the same time with two Hanna tests (at first, I thought one didn't work well).

I texted TM and they recommended that I stop dosing.

At the moment I have not added anything for two days and it maintains the 10,3 alk. I hope it goes down soon, because I'm losing corals.

If anyone has any experience with this I would greatly appreciate some advice!

 

[Randy Holmes-Farley]

I'd stop dosing and watch the alk longer.

 

[argiBK]

I’m pretty much still in the same boat a couple weeks later. Alk has maintained a range between 10.3 and 10.7 (testing 3x a day with KH Keeper). Calcium consumption has stabilized to 5ml dosing/day (and is the only thing I’m dosing at the moment).

Phophates and Nitrate are high at 0.9 (Hanna LR) and 20ppm (Hanna), but starting to get under control with Nopox and GFO. I’m assuming Phosphates took a leap from a recent Cyano outbreak (which has largely been eliminated with Calcium Carbonate + MB7 daily doses). Nevertheless, my corals are looking quite brown and I unfortunately had a small Acro colony RTN after a recent water change.

I’m assuming AFR precipitated alk somewhere in the system (none of the sand in the DT seems to have cemented however).

 

[Randy Holmes-Farley]

I’m pretty much still in the same boat a couple weeks later. Alk has maintained a range between 10.3 and 10.7 (testing 3x a day with KH Keeper). Calcium consumption has stabilized to 5ml dosing/day (and is the only thing I’m dosing at the moment).

Phophates and Nitrate are high at 0.9 (Hanna LR) and 20ppm (Hanna), but starting to get under control with Nopox and GFO. I’m assuming Phosphates took a leap from a recent Cyano outbreak (which has largely been eliminated with Calcium Carbonate + MB7 daily doses). Nevertheless, my corals are looking quite brown and I unfortunately had a small Acro colony RTN after a recent water change.

I’m assuming AFR precipitated alk somewhere in the system (none of the sand in the DT seems to have cemented however).

Declining nitrate adds alkalinity, and if you couple that with very low demand for demand for alk and calcium, then alk may be stable and you will not see any rise in calcium for an extended period because so little is dosed.

 

[argiBK]

Declining nitrate adds alkalinity, and if you couple that with very low demand for demand for alk and calcium, then alk may be stable and you will not see any rise in calcium for an extended period because so little is dosed.

Good to know, thank you! Does this also explain the fluctuating alk throughout the day? I test 3x, 8am, 4pm and 12pm and the pattern typically goes: 10.5-10.6, 10.3, 10.6-10.7. The 4pm reading is right after my light peak.

Should I just continue my current regimen with the aim of optimizing NO4 and PO4 and expect Alk and Cal consumption to eventually fall in line? I’d rather avoid doing a massive water change.

 

[WAfrican]

Good to know, thank you! Does this also explain the fluctuating alk throughout the day? I test 3x, 8am, 4pm and 12pm and the pattern typically goes: 10.5-10.6, 10.3, 10.6-10.7. The 4pm reading is right after my light peak.

Should I just continue my current regimen with the aim of optimizing NO4 and PO4 and expect Alk and Cal consumption to eventually fall in line? I’d rather avoid doing a massive water change.

Your alkalinity will fluctuate throughout a 24 hour period as it is tied to the PH of your tank which will vary from day to night. Generally testing at the highest and lowest ph times should give you your highs and lows for alkalinity as well excluding any dosing.

 

[Randy Holmes-Farley]

Your alkalinity will fluctuate throughout a 24 hour period as it is tied to the PH of your tank which will vary from day to night. Generally testing at the highest and lowest ph times should give you your highs and lows for alkalinity as well excluding any dosing.

That could well be the case, but IMO its an open question on how much of the alk demand increase during the day is due to elevated pH, and how much is a direct internal organism effect of coupling photosynthesis to calcification.

A tank with an inverted pH/daylight cycle would help answer that question.

 

[Gatorpa]

That could well be the case, but IMO its an open question on how much of the alk demand increase during the day is due to elevated pH, and how much is a direct internal organism effect of coupling photosynthesis to calcification.

A tank with an inverted pH/daylight cycle would help answer that question.

Agree I think as the pH rises due to metabolism (lights on) it has more of an effect due to consumption, at least that’s what my observations show in my own tank.
Hence I dose a two part Alk at the peak photo period to prevent it bottoming out. I also dose Kalkwasser at night in Top off.

This is in a 120 gallon with heavy live rock and SPS dominant.
Picture below for reference.