Alk Consuption has stopped ?

[Matt1508]

Hi All

Im loosing the plot a little bit trying to understand whats going on within my reef, ill try to include as much info as possible - any ideas would be greatly appreciated !

First off i use the powdered, mix your own Foundation Elements by Red Sea ALK and Calc ( no uptake in mag so dont dose ) they only other things i dose are 3ml Acropower Daily and KZ Coral Vitalizer 4 drops daily in a Red Sea 425Xl. Setup is predominantly SPS, mostly Acropora frags and smaller colonies and a few LPS. Tank is mature and just about to hit the 2 yr mark

Around a week and a half ago, i noticed some of my Acropora werent extending their Polyps as much as usual and didnt look quite as vibrant as usual, double checked my ALK and it had risen from 8.5 to 11.2, admittedly i hadnt checked my alk for around 2 weeks and assuming its was a gradual rise as none of the corals looked ill, as i would expect from a sudden swing of that size. im bringing the ALK back down by reducing dose at 0.2dkh daily. I was dosing 100ml and im now at 55ml and tank sits steady at 10.4 as of today - i think by the time i hit 8.5 ill likley be dosing nothing (5ml reduction in buffer reduces alk by 0.2)

Other Parameters are

Salinity steady at 1.026 (35ppt)
Phosphates 0.02 - 0.04
Nitrates 0 (need to bring up to around 3 -5 but struggling)
Calcium - 450 stopped dosing was at 470 but is almost stopped in consumption with the ALK as i would expect usually around 430
Mag 1280
Flow: 2 Gyre XF250, x1 Nero 5 and a Tunze 6095
Lighting : x2 Radion XR15 Gen 5 Blue, x 1 Hydra 52 and X4 T5 in a Hybrid Fixture
Nutrient Export: Refugium and Skimmer (Skimmer has been offline for around 3 months in an attempt to increase NO3)
Doser: Kamoer X4 - I have checked Calibration and manually dosed 5 and 10ml into measuring Cylinders and is accurate.

I understand there could be a million reason why, but why would my tank just stop consuming ALK ?

The only change ive made is fragging a Duncan Colony around 2 weeks ago, otherwise usual weekly W/C @ 20% (Red Sea Blue) and standard maintenance only

Cheers
Matt

 

[Randy Holmes-Farley]

I don't see an obvious cause.

I'd suggest just keeping monitoring, and double check the alk measurement with a different method.

 

[Matt1508]

I don't see an obvious cause.

I'd suggest just keeping monitoring, and double check the alk measurement with a different method.

Thanks Randy, ive checked with 2 Salifert kits and a Hanna all read within 0.1 of each other.. would this be typical of 0 Nitrates ? assuming theres never actually 0 nitrates in the system though regardless of what the test kit shows ?

 

[Randy Holmes-Farley]

Thanks Randy, ive checked with 2 Salifert kits and a Hanna all read within 0.1 of each other.. would this be typical of 0 Nitrates ? assuming theres never actually 0 nitrates in the system though regardless of what the test kit shows ?

Starving of corals might do that, yes. maybe dose or feed more.

 

[redeyejedi]

Agree on feeding more. Sounds like growth production has stopped.

 

[Matt1508]

Thanks both, Randy could your send me the link to the Sodium Nitrate calculator, assuming better than Potassium Nitrate ?

 

[Matt1508]

@Randy Holmes-Farley Ive found it from another post thanks, i would be using Sodium Nitrate does this look OK to raise by 1ppm daily

 

[Randy Holmes-Farley]

That's good. There's no need to distinguish sodium nitrate from potassium nitrate for this purpose of dosing amounts.

 

[Matt1508]

That's good. There's no need to distinguish sodium nitrate from potassium nitrate for this purpose of dosing amounts.

Thanks Randy

 

[Matt1508]

@Randy Holmes-Farley Hi Randy can you advise, so I started dosing small amounts of Sodium Nitrate as discussed raising from undetectable to 0.5ppm I now have Diatoms popped up brown on sand bed dusting on pumps and rocks, I thought this was usually in a low nutrients environment but I’m not sure if to stop dosing nitrates now or if to continue ? Currently No3 0.2 - 0.5 and PO4 is at 0.02

thanks again

matt

 

[Nano sapiens]

I had a very similar situation where Kalkwasser usage went from ratios of ~80% KalK/RO to ~5% Kalk/RO, so almost a dead stop. I had an Alk spike of 12.5 dKh (may have gone higher) over a month's time due to a faulty test kit and also a Mag spike of nearly 1800 ppm at around the same time. Most SPS showed obvious signs of distress (Montipora, Seriatopora, Leptoseris), Pavona did not.

I've seen this same Alk consumption turn off event twice in 12+ years. Both times, a sustained high Alk condition was involved (previous event Alk over 14 dKh).

 

[X-37B]

How many gallons is your system?
How many fish?
How much do you feed?

 

[Matt1508]

How many gallons is your system?
How many fish?
How much do you feed?

110g system, with a good bio load around 15 fish most small and a few tangs. System is a few years old now and usually stable. I have the Alk back under control and has been stable for a good few days now at 8.2. However I’m unsure if undetectable nutrients is my cause for corals to drop in alkalinity consuption and have started to raise them very slowly, the day after I started the diatoms appear, likely due to the change in nutrient levels but do I continue to raise or let the levels drop back. I have a refugium with cheato for organic and nutrient control that is now on a very small photoperiod and I guess it’s completely possible that whilst kits read low the macro algae is causing false low, me the adding No3 is too much and the diatoms are first in line ?

 

[Matt1508]

I had a very similar situation where Kalkwasser usage went from ratios of ~80% KalK/RO to ~5% Kalk/RO, so almost a dead stop. I had an Alk spike of 12.5 dKh (may have gone higher) over a month's time due to a faulty test kit and also a Mag spike of nearly 1800 ppm at around the same time. Most SPS showed obvious signs of distress (Montipora, Seriatopora, Leptoseris), Pavona did not.

I've seen this same Alk consumption turn off event twice in 12+ years. Both times, a sustained high Alk condition was involved (previous event Alk over 14 dKh).

Interesting, sounds very similar. I find it hard to let go though and need to understand why this occurred, seemingly stable for so long then as you say almost a complete switch off

 

[X-37B]

110g system, with a good bio load around 15 fish most small and a few tangs. System is a few years old now and usually stable. I have the Alk back under control and has been stable for a good few days now at 8.2. However I’m unsure if undetectable nutrients is my cause for corals to drop in alkalinity consuption and have started to raise them very slowly, the day after I started the diatoms appear, likely due to the change in nutrient levels but do I continue to raise or let the levels drop back. I have a refugium with cheato for organic and nutrient control that is now on a very small photoperiod and I guess it’s completely possible that whilst kits read low the macro algae is causing false low, me the adding No3 is too much and the diatoms are first in line ?

How much and what do you feed your fish every day?

 

[Matt1508]

How much and what do you feed your fish every day?

I feed two cubes of brine and 2 cubes of mysis in the morning between 3 tanks ( roughly 1 cube of each in this tank) and Ocean nutrition Formula 2 flakes in the evening. Occasionally add a sheet of Nori for the tangs once a week. I don’t feed the corals outside of Amino and Pohls Solution from KZ

 

[Nano sapiens]

Interesting, sounds very similar. I find it hard to let go though and need to understand why this occurred, seemingly stable for so long then as you say almost a complete switch off

That's a good question and I've puzzled over it, too. What is clear is that while 12+ Alk may be tolerated, it isn't a natural condition on any natural coral reef.

Doing a bit of Internet crawling, this study appears to be relevant:

https://reefs.com/magazine/the-effect-of-ph-alkalinity-and-calcium-on-hermatypic-corals/

"Aquarists most often maintain elevated levels of pH, alkalinity, and calcium to promote coral health. In this study however, elevated conditions of these parameters resulted in a decline of photosynthetic efficiency (Fv/Fm), indicating an overall decrease in coral health. There was also a slight decrease in health as parameter values increased within the recommended ranges. This effect should be considered when dosing in a closed system as corals experienced optimal health within the lower values of the recommended ranges."

The way I read this, sustained quite high alkalinity may have a negative effect on photosynthesis...which may then negatively influence the rate of calcification...which would then be obvious to us as a reduction in alkalinity usage.

That's about as close as I can get to a possible answer...

 

[Matt1508]

There’s no doubt that elevated Alk did not suit my tank, with low nutrients and fairly high par it was never going to go well.

just unsure now where to keep the nutrient levels, tank was happy at near zero but ultimately dropping to unreadable is the only change I can tell of that may have caused the issue, now I worry I’m feeding diatoms unnecessarily?? Will they burn out if I continue to rise or will I just create another issue lol I love this hobby ... but sometimes ..

 

[Randy Holmes-Farley]

That's a good question and I've puzzled over it, too. What is clear is that while 12+ Alk may be tolerated, it isn't a natural condition on any natural coral reef.

Doing a bit of Internet crawling, this study appears to be relevant:

https://reefs.com/magazine/the-effect-of-ph-alkalinity-and-calcium-on-hermatypic-corals/

"Aquarists most often maintain elevated levels of pH, alkalinity, and calcium to promote coral health. In this study however, elevated conditions of these parameters resulted in a decline of photosynthetic efficiency (Fv/Fm), indicating an overall decrease in coral health. There was also a slight decrease in health as parameter values increased within the recommended ranges. This effect should be considered when dosing in a closed system as corals experienced optimal health within the lower values of the recommended ranges."

The way I read this, sustained quite high alkalinity may have a negative effect on photosynthesis...which may then negatively influence the rate of calcification...which would then be obvious to us as a reduction in alkalinity usage.

That's about as close as I can get to a possible answer...

My interpretation is different: they starved the corals, and just like with burnt tips at high alk, the tissue could not keep up with skeletal growth and that messed everything up. It's not a high alk effect per se, it is high alk with insufficient N and P:

"Nitrate and nitrite generally peak when excess nutrients are added to a system which could cause stress among corals. It was important to maintain these at 0.00 mg/L during the entire duration of this experiment (Hughes et al. 2003). "

 

[Garf]

My interpretation is different: they starved the corals, and just like with burnt tips at high alk, the tissue could not keep up with skeletal growth and that messed everything up. It's not a high alk effect per se, it is high alk with insufficient N and P:

"Nitrate and nitrite generally peak when excess nutrients are added to a system which could cause stress among corals. It was important to maintain these at 0.00 mg/L during the entire duration of this experiment (Hughes et al. 2003). "

This baffles me. The tissue tissue causes the skeletal growth, unless it’s abiotic precipitation. Is that what happens?