Alkalinity is the only thing dropping.

James Mikell · May 2, 2019

Ok so im going to start having to dose my tank to keep my alk where i want it at 8.5 neither my calcium or my magnesium are moving but my alk drops about 1.3 dkh in 4 days. I have been hand dosing a few mils a day to keep it stable but It was always my understanding that alk and calcium would drop evenly hence why you dose 2 part evenly. Since my tank isnt high demand and mainly have a bunch of euphelia, acans and soft corals i thought dosing kalk would be a better solution. But would kalk raise my calcium super high since its not being used? And is there a good starting point for kalk dosage? I will be putting it on a dosing head and not in my ato.

cracker · May 3, 2019

Hey James, same thing with me ! I bet ya know this but You can dose just alk to get the reading you want then continue with the equal prts alk & Ca. let's hear what others have to say.

rcsbcoyote · May 3, 2019

My tank is the same way. I tunrned my calcium dose off completely for a few days.

Sabellafella · May 3, 2019

James Mikell said:
Ok so im going to start having to dose my tank to keep my alk where i want it at 8.5 neither my calcium or my magnesium are moving but my alk drops about 1.3 dkh in 4 days. I have been hand dosing a few mils a day to keep it stable but It was always my understanding that alk and calcium would drop evenly hence why you dose 2 part evenly. Since my tank isnt high demand and mainly have a bunch of euphelia, acans and soft corals i thought dosing kalk would be a better solution. But would kalk raise my calcium super high since its not being used? And is there a good starting point for kalk dosage? I will be putting it on a dosing head and not in my ato.

Hey! I'm not sure of the exact proportion but for every 1 dkh, is ruffly 6-7 ppm calcium. Over the course of 4 days you may not even see that spread on results with a typical hobbiest test kit(calcium). Hence giving you the illusion, of your tank not taking in calcium. Common question people ask all the time. Use both parts equally to keep an ionic balance opposed to just adding sodium and not the chloride.

James Mikell · May 3, 2019

cracker said:
Hey James, same thing with me ! I bet ya know this but You can dose just alk to get the reading you want then continue with the equal prts alk & Ca. let's hear what others have to say.

Yeah im using reef fusion seachem to get the alk where i want i just wasnt sure if i start dosing calcium in an equal part would my calcium start climbing out of control instead of just maintaining

James Mikell · May 3, 2019

Sabellafella said:
Hey! I'm not sure of the exact proportion but for every 1 dkh, is ruffly 6-7 ppm calcium. Over the course of 4 days you may not even see that spread on results with a typical hobbiest test kit(calcium). Hence giving you the illusion, of your tank not taking in calcium. Common question people ask all the time. Use both parts equally to keep an ionic balance opposed to just adding sodium and not the chloride.

Once i get my alk where i want it then would i just be better off running kalk to maintain since its such a low demand tank?

homer1475 · May 3, 2019

In 10 years of owning a marine aquarium, I have never dosed ALK and CAL in equal parts.

James Mikell · May 3, 2019

homer1475 said:
In 10 years of owning a marine aquarium, I have never dosed ALK and CAL in equal parts.

Good to know im not going to go crazy chasing my tail. Thank you. I see this being the norm the more i read about it

homer1475 · May 3, 2019

I think the reason we see this in the hobby is because of the relative small drop in CAL in regards to the rather large drop in ALK. As @Sabellafella pointed out this relatively small drop cannot be picked up on our hobby grade test kits.

With that said, I do see a small drop in CAl by weeks end. So I hand dose back up what my WC doesn't replace, but I still dose ALK daily.

Randy Holmes-Farley · May 4, 2019

James Mikell said:
Ok so im going to start having to dose my tank to keep my alk where i want it at 8.5 neither my calcium or my magnesium are moving but my alk drops about 1.3 dkh in 4 days. I have been hand dosing a few mils a day to keep it stable but It was always my understanding that alk and calcium would drop evenly hence why you dose 2 part evenly. Since my tank isnt high demand and mainly have a bunch of euphelia, acans and soft corals i thought dosing kalk would be a better solution. But would kalk raise my calcium super high since its not being used? And is there a good starting point for kalk dosage? I will be putting it on a dosing head and not in my ato.

You will not be able to reliably detect the small calcium drop (2 ppm per day) that is expected to accompany that drop in alkalinity (0.3 dKH per day), even if it all comes from calcium carbonate formation.

If you dose a good two part evenly, you also would not be able to reliably detect the small calcium rise, even if there truly was ero calcium usatge.

Thus, I recommend sticking with equal parts dosing based on alk unless you really verify over long time periods that calcium is rising higher than you want (say, 500+ ppm)

Randy Holmes-Farley · May 4, 2019

James Mikell said:
Once i get my alk where i want it then would i just be better off running kalk to maintain since its such a low demand tank?

Limewtaer (kalkwasser) is actually slightly imbalanced to to much calcium, when a properly designed two part isn't.

Randy Holmes-Farley · May 4, 2019

James Mikell said:
Good to know im not going to go crazy chasing my tail. Thank you. I see this being the norm the more i read about it

Actually, people who do test very carefully, and who are not seeing effects due to water changes with a mix not matching the tank. will usually find the demand is VERY close to 18-20 ppm calcium for each 1-2 meq/L (2.8 dKH) of alkalinity. People run for months with balanced systems without big issues. Especially CaCO3/CO2 reactor users. Why? Probably because they cannot keep fiddling or mistakenly dose unequal amounts.

The big reason for imbalanced demand (aside from water changes), is sulfur denitrators (they consume alkalinity) or rising or falling nitrate (it depletes/adds alkalinity).

cracker · May 4, 2019

Good reminder Randy ! Thanks

James Mikell · May 4, 2019

Randy Holmes-Farley said:
You will not be able to reliably detect the small calcium drop (2 ppm per day) that is expected to accompany that drop in alkalinity (0.3 dKH per day), even if it all comes from calcium carbonate formation.

If you dose a good two part evenly, you also would not be able to reliably detect the small calcium rise, even if there truly was ero calcium usatge.

Thus, I recommend sticking with equal parts dosing based on alk unless you really verify over long time periods that calcium is rising higher than you want (say, 500+ ppm)

I just read all your responces and i thank you very much for your input. I will start dosing my 2 part in equal portions then.

homer1475 · May 5, 2019

Pretty sure I can go back on RC and find a thread where @Randy Holmes-Farley specifically told me that 2 part does not have to added in equal parts. I know I can because I specifically asked him that question years ago.

Randy Holmes-Farley · May 5, 2019

homer1475 said:
Pretty sure I can go back on RC and find a thread where @Randy Holmes-Farley specifically told me that 2 part does not have to added in equal parts. I know I can because I specifically asked him that question years ago.

It's fine to do, whether it is real, or just the result of dosing pumps not exactly performing to specs, etc.

I would just suggest for folks to not jigger the dosing every couple of days, but adjust based on long term trends.