Raising Calcium but not alkalinity

[Miami Reef]

I'm running sps heavy and was seeing a great deal of calcium depletion. Perhaps 500 is too high and I should have targeted 450. I wasn't seeing alk drop, it was just rising and rising, so adding ESV 1:1 as directed wasn't working. I'm open to the idea I may have done something wrong, but I don't know what.

Faulty calcium kit is my prediction. Acropora, corals, and coralline algae cannot consume calcium without also consuming alkalinity.

A more realistic scenario would be seeing alkalinity drop, but hardly noticing calcium move.

 

[Randy Holmes-Farley Verified Community Expert]

I'm running sps heavy and was seeing a great deal of calcium depletion. Perhaps 500 is too high and I should have targeted 450. I wasn't seeing alk drop, it was just rising and rising, so adding ESV 1:1 as directed wasn't working. I'm open to the idea I may have done something wrong, but I don't know what.

Well, I thought we made it clear, but here it is again:

1. A two part is always used to offset demand. Demand from corals is about 2.8 dKH per 18-20 ppm calcium.

2. You used it to boost calcium by a significant margin, a use it is not intended for, so alkalinity rose too much. A 60 ppm boost to calcium would send alk up by more than 8 dKH.

If your spouse said to come home with 2 pounds of ham, and you came home with 13 ham and cheese sandwiches, would it be surprising if the cheese and bread piled up on the table?

Use ESV as directed, 1:1 dosing, to offset normal calcium and alkalinity consumption, not to make corrections to give a big boost to calcium. Saw the dose off alkalinity.

That said, calcium will be equally good between 400 and 550 ppm in any reef aquarium.

 

[AquaLogic]

Well, I thought we made it clear, but here it is again:

1. A two part is always used to offset demand. Demand from corals is about 2.8 dKH per 18-20 ppm calcium.

2. You used it to boost calcium by a significant margin, a use it is not intended for, so alkalinity rose too much. A 60 ppm boost to calcium would send alk up by more than 8 dKH.

If your spouse said to come home with 2 pounds of ham, and you came home with 13 ham and cheese sandwiches, would it be surprising if the cheese and bread piled up on the table?

Use ESV as directed, 1:1 dosing, to offset normal calcium and alkalinity consumption, not to make corrections to give a big boost to calcium. Saw the dose off alkalinity.

That said, calcium will be equally good between 400 and 550 ppm in any reef aquarium.

Thank you, I actually did not understand that ESV could not be used just to raise calcium alone, that clarifies it for me.

 

[AquaLogic]

Faulty calcium kit is my prediction. Acropora, corals, and coralline algae cannot consume calcium without also consuming alkalinity.

A more realistic scenario would be seeing alkalinity drop, but hardly noticing calcium move.

Thanks for the suggestion, I will test it against another kit to determine if it is bad.

 

[DanyL]

I use esv 2 part and my calcium creeps up to 500 and I back off for a while on dosing it.

Just wanted to add a different angle as to why this might happen for some folks.

What I found is that the Alk and Ca lines will loose calibration at different rates, likely due to a thin build up coating the tubes inside.

Overtime this may influence the perceived consumption rates, and in turn cause a 1:1 dosing method to slightly drift apart.

 

[exnisstech]

Just wanted to add a different angle as to why this might happen for some folks.

What I found is that the Alk and Ca lines will loose calibration at different rates, likely due to a thin build up coating the tubes inside.

Overtime this may influence the perceived consumption rates, and in turn cause a 1:1 dosing method to slightly drift apart.

That makes perfect sense but I would have to make adjustments when manually dosing. To be honest I never really thought much about it. I manually dosed esv 2 part for several years on two tanks and I always ran out of the alkalinity supplement and still had calcium left. I didn't keep good records but I do remember several months dosing 30ml alk to 20ml calcium on my 180. I dosed every morning before leaving for work.
I'm not challenging the science or anything like that. I just seem to have weird stuff that goes on that shouldn't be and I just accept it. Kalk and pH for instance. I read about all these folk running kalk for the pH boost. For a little over a year I had 2 tanks on 2 part and another that got 7200ml of fully saturated kalk daily yet when I measure pH all 3 would be identical.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not challenging the science or anything like that. I just seem to have weird stuff that goes on that shouldn't be and I just accept it. Kalk and pH for instance. I read about all these folk running kalk for the pH boost. For a little over a year I had 2 tanks on 2 part and another that got 7200ml of fully saturated kalk daily yet when I measure pH all 3 would be identical.

There’s nothing you stated that seems unusual.

While the pH boist of kalk is twice as much as a carbonate two part, the degree of effect depends on the aeration and the amount dosed. Even at higher doses, enough aeration will drive down the effect. It’s not at all an effect like dosing calcium and getting a fixed change.

There are many minor things that impact the consumption of alk, such as nitrate rising, falling, or being dosed, and if the total alk demand is on the low end, these can dominate the measured ratio. Water changes can also mess up the demand ratio.

 

[DanyL]

That makes perfect sense but I would have to make adjustments when manually dosing. To be honest I never really thought much about it. I manually dosed esv 2 part for several years on two tanks and I always ran out of the alkalinity supplement and still had calcium left. I didn't keep good records but I do remember several months dosing 30ml alk to 20ml calcium on my 180. I dosed every morning before leaving for work.
I'm not challenging the science or anything like that. I just seem to have weird stuff that goes on that shouldn't be and I just accept it. Kalk and pH for instance. I read about all these folk running kalk for the pH boost. For a little over a year I had 2 tanks on 2 part and another that got 7200ml of fully saturated kalk daily yet when I measure pH all 3 would be identical.

I’ve always made my own supplements, so I don’t have any experience with ESV, nor knowledge on their concentrations.

If that’s a 1:1 system with the Alk being based on bicarbonate, 10 mls isn’t as big of a difference as there might be other things that may influence your alkalinity levels as Randy mentioned.

What I described in my reply was just another reason as to why a perceived drift between the two might happen, just from my personal observation over the years.


As for the PH - that makes perfect sense actually.

I have 2 systems: one in a living room (main system), and the other in a bed room (frag tank) - both have very similar consumption rates.

The main system (206g) is in a large and well aerated room, and in addition to this also has a large portion of its sump dedicated for frags where the lighting schedule is in reverse to the display. It always hovers around 8.1-8.2 PH, dosing (tons of) bicarbonate.

The frag tank (90g) on the other hand, is in a relatively small room, is less aerated and the PH fluctuates across the day, and depends also on the season of the year.

With the frag tank I switched from using bicarbonate, to carbonate and finally to sodium hydroxide and the PH now is hovering between 8 to 8.3 - which is pretty much the same as my main system, even though one uses extremely high PH supplement and the other net-natural.

I think that very same scenario is what your are experiencing with your tanks as well.