ALK consumption
- Thread starter svreef
- Start date
This is a typical Alk dosing regimen for me. I have it broken down in 4 groups, with the timing corresponding to when my Trident reads 4 times a day. If the Alk readings are coming in consistently low or high at a certain time of day, I raise or decrease (respectively) the dosing for the 6 hours preceding that Trident sampling time.
So for example if my 18:00 Trident readings are coming in consistently low I’ll slightly raise my 12:01-18:00 dosing amount.
The exact numbers aren’t important, and I’m tweaking them frequently anyway as my tank needs more or less dosing. The trend is consistent though. To keep it easy I increase or decrease my Ca and Mg solutions (I’m using Triton) by 5 ml/day at a time, then add/subtract 5 ml to 2 different time points (Triton doses twice as much Alk as the other 2).
1 thing I was surprised about by taking this approach-
Clearly Alk consumption correlates with photoperiod as we all expect, but there is considerable Alk consumption happening for hours after the photoperiod. This makes sense from a biological perspective if you think of photosynthesis as the fuel that allows growth, and it takes several hours for the coral to run out of the fuel they’ve accumulated that day. Even the 12a-6a period needs some small amount of dosing or else the Alk level drops significantly.
This approach also makes apparent something that I disagree with that is commonly done. Lots of people set up a baseline dosing level, and then let their Apex dose a little more or less based on the last Trident reading. If you do this, you will always be in catch-up mode, dosing more AFTER you dosed too little and the Alk dropped, then dosing less AFTER you dose too much and the Alk is too high.
So for example if my 18:00 Trident readings are coming in consistently low I’ll slightly raise my 12:01-18:00 dosing amount.
The exact numbers aren’t important, and I’m tweaking them frequently anyway as my tank needs more or less dosing. The trend is consistent though. To keep it easy I increase or decrease my Ca and Mg solutions (I’m using Triton) by 5 ml/day at a time, then add/subtract 5 ml to 2 different time points (Triton doses twice as much Alk as the other 2).
1 thing I was surprised about by taking this approach-
Clearly Alk consumption correlates with photoperiod as we all expect, but there is considerable Alk consumption happening for hours after the photoperiod. This makes sense from a biological perspective if you think of photosynthesis as the fuel that allows growth, and it takes several hours for the coral to run out of the fuel they’ve accumulated that day. Even the 12a-6a period needs some small amount of dosing or else the Alk level drops significantly.
This approach also makes apparent something that I disagree with that is commonly done. Lots of people set up a baseline dosing level, and then let their Apex dose a little more or less based on the last Trident reading. If you do this, you will always be in catch-up mode, dosing more AFTER you dosed too little and the Alk dropped, then dosing less AFTER you dose too much and the Alk is too high.
RandyC
Supporting Member
Corals can and do grow at night. They use respiration to do so, but the growth is slower compared to photosynthesis as it does cost more energy to do it. Also, don’t forget snails and crabs need Alk/Ca/Mg as well and don’t depend on light cycle. When my trochus snails bred, I’ve seen them consume 1dkh a day in 90ish gallon tank by volume.
The_Lazy_Reefer
Supporting Member
I lose about 1.5dkh daily and I imagine if I switched from a mixed reef to all sps that number would climb even higher.
Ibn
Guest
Over 1 dkh daily if I was to pull the calcium reactor offline on ~20G tank. As to actual, I haven't actually measured and don't really want to mess with the corals with such a new tank and limited reserves/tolerances on such small frags. Just an observation as I was manually dosing to bring levels up before letting the reactor take over.
Alk chart from Trident, where I'm usually hovering in the 8.5 dkh. The two spikes are noted when I was manually testing some water from another reefer's tank.
Testing 4x daily with the Trident (6 am, noon, 6 pm, midnight), with some manually testing in between the daylight hours to see how Alk drifts as I tune in the reactor. At noon, it peaks in at ~8.5.
It drifts down slightly throughout the day as the tank is lighted with it dropping down a bit at midnight. The solenoid, recirculation, and feed pumps are kept on a bit longer than the lighted hours since there's a ramp down of their process. It's helped me to flatten the curve.
Alk chart from Trident, where I'm usually hovering in the 8.5 dkh. The two spikes are noted when I was manually testing some water from another reefer's tank.
Testing 4x daily with the Trident (6 am, noon, 6 pm, midnight), with some manually testing in between the daylight hours to see how Alk drifts as I tune in the reactor. At noon, it peaks in at ~8.5.
It drifts down slightly throughout the day as the tank is lighted with it dropping down a bit at midnight. The solenoid, recirculation, and feed pumps are kept on a bit longer than the lighted hours since there's a ramp down of their process. It's helped me to flatten the curve.
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Mike Yasin
Guest
3 to 4 dkh in ~108 gallons. Depends on pH level, but low end is roughly 2.5 to 3 dkh, I'm SPS heavy - frags and mini colonies
Well, there is another possibility - the Alk is not actually changing like that.
My measured Salinity shows variations that I know are impossible. Alk might be similar.
Many automated Alk tests use a function based on changing PH.
PH really does swing, and could certainly affect readings.
Similarly, temperature and other factors could affect it.
My measured Salinity shows variations that I know are impossible. Alk might be similar.
Many automated Alk tests use a function based on changing PH.
PH really does swing, and could certainly affect readings.
Similarly, temperature and other factors could affect it.
The ca I started dosing was precipitating and becoming a solid chunk. That, however could be because of my dosing tube setup which I’ve also fixed.
Blaise006
Supporting Member
I would love to see your alk chart. Your ratios are almost exact to mine.
1Pure speculation, but do you get get random .1-.25 dkh drops in the 12-18 window?
2) What does your PH swing look like?
3) what’s your peak photo intensity and timeslot?
I am really interested in what you have to say, apologies for the barrage of questions.
max_nano
Supporting Member
I had something similar happened and realize it was because during a water change the water level would go up high enough that some tank water would touch the tip of the dosing tube. Changing the tube out and putting the mount higher stopped that.
Could the water level in that chamber touch the end of the dosing tubes ever? That may be what caused that stalactite
Could the water level in that chamber touch the end of the dosing tubes ever? That may be what caused that stalactite
My Alk chart:
(A few days ago it was drifting up too much, so I paused dosing for a couple hours and it came back down to target with 1 spurious reading, I lowered dosing but I guess too much because then it drift downward slowly and I just increased it a little again across the board)
My pH chart:
Pretty much like clockwork.
My photo peak is 10a-6p with basically 2 hour tails.
Chromis
Supporting Member
I spiked the alk in my tank this week by accident, which was a perfect opportunity to see how much alk drops! I turned off my alk dosing a couple days and was able to observe my alk drop 1.56dKh over 24h. There was under 0.2dKh drop between 9pm and 6am, implying photosynthesis drives >90% of the alk drop in my tank.
The nice thing about having a Trident, besides catching the spike, is I was able to watch for signs of shock afterward and time turning the alk doser off and back on. The acros in my tank didn’t even blink but I did lose one out of a dozen urchins, not sure if related, but I never lost a single urchin before.
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Coral reefer
Past President
Damn, 12 urchins?!?
Chromis
Supporting Member
I prefer them to snails. They came in nickel-sized from ORA, but are now 2-3cm and actually I need to move more of them to the garage tank since the coralline is getting scarce on the back glass (good for me, bad for them). You used to be able to get them much cheaper from ORA/live aquaria before everything got expensive in the hobby this past year.
thesassyindian
Supporting Member
I don't have fancy Apex systems, but in my tiny 13gal tank, with some SPS, my Alk drops from 9.5dKH to 7.7dKH overnight.
My daily dosage of ESV-B Ionic is 12.5ml (Manual doses of 7.5ml in the morning, and 5ml at around 9pm)
Calcium hovers around 425ppm, and Magnesium around 1310ppm.
My daily dosage of ESV-B Ionic is 12.5ml (Manual doses of 7.5ml in the morning, and 5ml at around 9pm)
Calcium hovers around 425ppm, and Magnesium around 1310ppm.