Alk/Cal imbalance question for Randy

scottsreef · Jun 13, 2018

Hi Randy I am dosing your 2-part system. I dose equal amounts of each but my Alk is at 6.7 after 2 weeks and Cal is up to 600 in same time frame. Should i add more Alk solution to bring it up or dose more calcium? Im using Red Sea blue bucket regular salt. Thanks in advance
Scott

lapin · Jun 13, 2018

Logic says. What is low needs more and what too high needs less.

Greenstreet.1 · Jun 13, 2018

You can dose more alk than cal or less cal and more alk it will not be a problem but it looks like you are just dosing you should be dosing to replace what your tank consumes.
You should stop dosing cal till it drops to where you want it and raise the alk to where you want it. Then see how much of each your tank consumes a day and dose to replace that.

I hope I explained that correctly [emoji848]

scottsreef · Jun 13, 2018

Greenstreet.1 said:
You can dose more alk than cal or less cal and more alk it will not be a problem but it looks like you are just dosing you should be dosing to replace what your tank consumes.
You should stop dosing cal till it drops to where you want it and raise the alk to where you want it. Then see how much of each your tank consumes a day and dose to replace that.

I hope I explained that correctly [emoji848]

It was balanced and at levels I wanted 2 weeks ago and in 2 weeks with balanced dosing it has gone out that much.

Greenstreet.1 · Jun 13, 2018

scottsreef said:
It was balanced and at levels I wanted 2 weeks ago and in 2 weeks with balanced dosing it has gone out that much.

Did you do a water change and then it changed ? What did you do differently for that to happen if nothing then you did not have the correct daily dose.

scottsreef · Jun 13, 2018

Greenstreet.1 said:
Did you do a water change and then it changed ? What did you do differently for that to happen if nothing then you did not have the correct daily dose.

I did a water change but new salt was at levels I’m matching in tank. I checked levels and then 3 days later I checked alk to see what demand was and set my dosing to those numbers.

Greenstreet.1 · Jun 14, 2018

Then are you sure it’s not a testing error ? And I’m assuming you tested the new mix of water.

scottsreef · Jun 14, 2018

Greenstreet.1 said:
Then are you sure it’s not a testing error ? And I’m assuming you tested the new mix of water.

I use Salifert test kits and Hanna checkers and yes new mix was same as levels I am shooting for. Just not sure why cal would go up so high and alk drop with a balanced dose. I might have to stop dosing and recheck the tank demand.

Greenstreet.1 · Jun 14, 2018

scottsreef said:
I use Salifert test kits and Hanna checkers and yes new mix was same as levels I am shooting for. Just not sure why cal would go up so high and alk drop with a balanced dose. I might have to stop dosing and recheck the tank demand.

Well if the level was at what you are going for then I can see why the cal may have jumped if dosing started and it was at where you wanted it but I can’t see why the alk would drop.

How long did it take for this to happen ?

sstanley223 · Jun 14, 2018

Wouldn't high calcium drive down alkalinity? I wonder what the magnesium level is?

Frogger · Jun 14, 2018

Your hard corals, snails and coraline algae all use calcium and carbonate to build their skeletons at the exact same ratio as you add with the 2 part solution. Not sure why your calcium is out of wack. You may want to double check your test kits. I always have different brands of test kits I use when the values do not seem to be correct.
I would hesitate from adding more alkalinity additive than calcium as you could cause serious problems.

Best option is to do several large water changes to get things back to normal.

Randy Holmes-Farley · Jun 14, 2018

Unless you use a sulfur denitrator (which is an alkalinity hog), I cannot see such an imbalance in consumption happening in 2 weeks. Perhaps something got mixed or dosed incorrectly.

It is fine to stop dosing calcium if the result is real, but I spend time to figure out if the result is actually real and why it might have happened.

Randy Holmes-Farley · Jun 14, 2018

lapin said:
Logic says. What is low needs more and what too high needs less.

Perhaps. But logic also suggests the presented scenario is unusual and unexpected, and may have other explanations that are not best solved by just dosing less (like a faulty test kit, a dosing pump malfunction, etc,)

dkevink · Jul 8, 2018

I had something similar happen. Calcium went to 600 while I was trying to maintain an alk of around 9. I was dosing the Red Sea ABC+ based on my alk reading. I overdosed calcium and had a buildup of calcium in sump where I was dosing.

I did what Randy suggested and just dosed alk until the calcium dropped. Calcium took a while to drop because the calcium buildup in sump kept dissolving until it was all dissolved, calcium levels stayed high.

Randy Holmes-Farley · Jul 9, 2018

dkevink said:
I had something similar happen. Calcium went to 600 while I was trying to maintain an alk of around 9. I was dosing the Red Sea ABC+ based on my alk reading. I overdosed calcium and had a buildup of calcium in sump where I was dosing.

I did what Randy suggested and just dosed alk until the calcium dropped. Calcium took a while to drop because the calcium buildup in sump kept dissolving until it was all dissolved, calcium levels stayed high.

FWIW, I think calcium stayed high just because it is very slow to decline naturally. Calcium carbonate deposits in a tank are not likely to redissolve (seawater is already supersaturated with respect to calcium carbonate, which is why corals make skeletons of it), and if they do dissolve, they will add about 2.8 dKH for each 18-20 ppm of calcium released. So it boosts alk by a higher percentage than calcium.

dkevink · Jul 9, 2018

The Red Sea ABC+ did dissolve from sump. I had a white residue on bottom of sump and over time it disappeared as I only dosed alk. Maybe since it didn’t participate out, it was just the powder on bottom of sump. It kept my calcium high for weeks.

Randy Holmes-Farley · Jul 9, 2018

dkevink said:
The Red Sea ABC+ did dissolve from sump. I had a white residue on bottom of sump and over time it disappeared as I only dosed alk. Maybe since it didn’t participate out, it was just the powder on bottom of sump. It kept my calcium high for weeks.

That white material may have been magnesium hydroxide. It temporarily precipitates when a high pH alk solution is added to seawater, but it will redissolve as it mixes in.