Calcium / Ak Relationship

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elasmovideo

New Member
:swmfish: Can someone please explain the Ca / Ak relationship in simple/layman terms. My Ca is 'off the chart' (36 drops to get the tube to change colors. The chart only goes up to 26!).

I haven't been adding any Ca additive or Purple Up to the tank for about a week now and my Ca has only dropped slightly. My lfs is out of Ak test kits too so I have no way of measuring it.

Should I do a water change or just wait until the calcium goes down by itself. As of now I ownly have a FOWLR tank but I'm trying to build up the purple coraline. For fish, I only have 8 very small blue damsels.

Thanks in advance for the information which I know will be forthcoming!!

Pete
 
GrendelPrime

GrendelPrime

Well-Known Member
IMO i would do some water changes over the next few days to drop the ca a bit, and how old is the tank, if its new it might take alittle while for the coraline to start to grow all on its own check ur mag also chances are theres gonna be alot out of wack when u use stuff like purple up
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
Can someone please explain the Ca / Ak relationship in simple/layman terms. My Ca is 'off the chart' (36 drops to get the tube to change colors. The chart only goes up to 26!).

What we mean by balance is. We have what we call a starting point of 360 ppm Calcium with a Alk of 0 dKH. If we no raise the calcium to 380 the balanced Alk is 2.8 dkH. If we raise it 20 ppm to 400 that balanced Alk is 5.6 dKH, at 420 ppm , 11.2 dkH. So, if one is adding 20 ppm you should be raising the dKH 2.8 dKH, unless that Alk is already high enough.

So, 7 ppm Ca per 1 dkH

If your calcium is at 417 ppm, then

417 - 360 = 57

57 / 7 = 8.15 dkH for 417 ppm

This does not have to be exact and we usually run it a tad higher, So, 417 @ 8.5 or 9 dKH is fine.

I haven't been adding any Ca additive or Purple Up to the tank for about a week now and my Ca has only dropped slightly. My lfs is out of Ak test kits too so I have no way of measuring it.

That is your issue. PU does not raise calcium. There are multiple issuet with product like these.

1. PU adds no calcium, as the aragonite in it can not dissolve to raise the calcium

2. The powdered aragonite in the PU can pull calcium out of the water, as calcium like to attach to the particles of the powdered aragonite.

3. At times these floating particles can get in your test kit and give false high readings. What more than likely is your issue.



Should I do a water change or just wait until the calcium goes down by itself. As of now I ownly have a FOWLR tank but I'm trying to build up the purple coraline. For fish, I only have 8 very small blue damsels.

Yes a WC to get all that crap out and stop using it.
 
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Boomer

Boomer

Reef Sanctuary's Mr. Wizard
To add more to this balance issue. If Calcium leaves solution, meaning your tank has lost 20 ppm calcium, you also lost 2.8 dkH Alk. When that 20 ppm calcium leaves it takes 2.8 dKh with it. Similarly, if you tank looses 20 ppm magnesium you also loose 2.8 dKH. This does not work in reverser where many get confused. Meaning, if you loose 2.8 dkH you will use loose less than 20 ppm calcium. Alk is used for other things besides calcium and magnesium. It is used for example to help buffer the water. Thus, if you lost 20 ppm you could loose like 3.2 dkH and 2.8 of that 3.2 is for calcium and magnesium. So, 0.4 dkH went to other non-calcium-magnesium reactions.
 
M

mos90

Member
is it common for magnisium to drop enough to effect alk? i dont normally dose mag, just 10% water changes a month. last time i tested it was around 1300.

my water volume with my sump is 42g. medium coral and fish load. lights on for 12tank/12 fuge. im using twofishies a&b. it seems that i have to dose for alk everyday(50ml of alk b in 1300ml of ro/di water in a drip doser lasts about 5 days) calcium is about 420ppm. dosing manually 10ml every other day. im going to stop dosing calcium for a few day to see how much it drops.

if i stop dosing alk it WILL fall lower then 7dkh in a few days and the ph will drop below an acceptable level

i should ckeck my mag again to see if it has dropped. this could be why i have to dose alk so much. i may need a mag dosing schedule also.
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
is it common for magnisium to drop enough to effect alk?[b/]

Yes, as Mg++ helps stop abiotic precip of CaCO3. So, you loose Alk from the formation of CaCO3 (solid)
 
M

mos90

Member
thanks boomer.

i will recheck mag tonight. maybe raise it to 1350.

what would cal03 in in a solid form resemble. just so i can watch for it.
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
It is a whitish coating that looks like hard water deposits. It may be on equipment or dust like coating on the bottom. If there are fresh sand surfaces it will coat then and you will not see it.
 
M

mos90

Member
none of that yet. but mag may still be a little low. ill post test results tonight.

i hate testing. thats why i made drip systems for my 2 large freshwater tank. no waterchanges or testing to do..ph montiors on both tanks. once a week glass scraping thats it. besides feeding..

but once i get the hang of this tanks needs,testing should be minimal.
 
M

mos90

Member
so basically based on your tanks needs. its not uncommon to have to dose alk daily?

im still monitoring calcium loss to see how often i need to dose. im sure it will be less then alk.
 
Boomer

Boomer

Reef Sanctuary's Mr. Wizard
No, it is not as the Alk is used by many reaction not just for cor building. When acid are produce in a tank the ALk "buffers" them out or neutralizes them. An old Alk term in Limnology is Alk = ANC ( Acid Neutralizing Capacity) The Alk drops much faster than the Alk and the Alk is much more noticed, as there is so much more Calcium than Alk.
 
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