Alk dropping but high Calcium/Magnesium

[ReefSTX]

I'm not sure exactly how much of what you are dosing and when, but the calcium values moving around between 420 and 460 may just be reflecting testing variations on the same approximate calcium number. :)

Thanks Randy :)

Yes, I think you are correct. I just did a Cal and Alk test this morning; Cal 420, ALk 8-9 (Mg 1380). I suppose what I am seeing is the range in which my reef consumes these elements?

I dose AquaForest components 1+2+3+, at 5ml each daily.

 

[Randy Holmes-Farley]

I expect the calcium is fairly stable at about the average of those values, except it is higher just after dosing than just before.

 

[Mangelotta1]

I'm looking for a bit of insight. My alk is dropping and my Ca is rising. My understanding via Randy is I should dose more of both 2 part, AlK and Ca? I'd appreciate any input though. Thanks

 

[User1]

That is what many folks see because of the math of the ratio of consumption and the accuracy/precision of our test kits.
Here's my comment from an article:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-12/rhf/index.htm

Apparent Excess Demand for Alkalinity

One of the most common complaints of new aquarists is that their aquaria seem to need more alkalinity than their balanced additive system, such as limewater, is supplying. While there are reasons this may actually be the case over the long term (these will be detailed later in this article), frequently these aquarists are seeing a "chemical mirage" rather than a real excess demand for alkalinity.

One of the interesting features of seawater is that it contains a lot more calcium than alkalinity. By this I mean that if all of the calcium in seawater (420 ppm; 10.5 meq/L) were to be precipitated as calcium carbonate, it would consume 21 meq/L of alkalinity (nearly 10 times as much as is present in natural seawater). In a less drastic scenario, let's say that calcium carbonate is formed from aquarium water starting with an alkalinity of 3 meq/L that it is allowed to drop to 2 meq/L (a 33% drop). How much has the calcium declined? It is a surprise to many people to learn that the calcium would drop by only 20 ppm (5%). Consequently, many aquarists observe that their calcium levels are relatively stable (within their ability to reproducibly test it), but alkalinity can vary up and down substantially. This is exactly what would be expected, given that the aquarium already has such a large reservoir of calcium.

So the first "deviation" from the rule of calcium and alkalinity balance really isn't a deviation at all. If an aquarist is supplying a balanced additive to his aquarium, and calcium seems stable but alkalinity is declining, it may very well be that what is needed is more of the balanced additive, not just alkalinity. This scenario should be assumed as the most likely explanation for most aquarists who should look for more esoteric explanations for alkalinity decline only if calcium RISES substantially while alkalinity falls. Likewise, if alkalinity is rising and calcium seems stable when using a balanced calcium and alkalinity additive system, the most likely explanation is that too much of the additive system is being used.

The real imbalance effects described later in this article take effect slowly, and are manifested over weeks, months and years. This short term "chemical mirage" caused simply by the mathematics of calcium and alkalinity additions can be seen in a single addition. Any effect that develops rapidly over the course of a few days is almost certainly not a true imbalance.

The following scenarios show what can happen to a reef aquarium whose dosage with a balanced additive system does not match its demand. Table 1 shows what can happen when the dosing is inadequate. Alkalinity drops fairly rapidly. After two days, many aquarists might conclude that they need additional alkalinity, when in reality, they need more of both calcium and alkalinity to stabilize the system.

Table 2 shows what happens when too much of a balanced additive is added. After a few days, many aquarists would conclude that alkalinity is rising too much, but that calcium is fairly stable. Again, what is needed is less of the balanced additive, not just less alkalinity.

I know this thread is over a year old but this was the first thread that came up during a search outside the portal. I've been trying to understand why my Calcium is increasing while only adding Alkalinity. I've been prepping to add both using ESV 2 part but since I'm only seeing a decrease in Alk I started to dose 12 ml a day on my 210 gallon tank/upgrade. I actually started at 6 ml then increased it over a couple days to 12 ml to see if it changed and it hasn't. I only see my Calcium increasing.

In your example above and when compared to what I see - I am seeing the imbalance. I've manually dosed 20 ml of ESV 2 part Alk only and it raised my ALK to 8.1 (I'm trying to keep it around 8.5). I assumed dosing the Alk component only would increase it but so far all I see happening is my Calcium raising over 600 (assuming the trident is correct - it is when I test Alk manually).

I'm reading the entire article you posted again but since stopped the Alk dose to see if Calcium falls. Should I dose both parts in a low amounts instead and see what happens? The tank is doing well so do not want to over do anything. Rock is maturing as are the test corals I've added and the tank is 18 months into its upgrade.

 

[Randy Holmes-Farley]

Adding just alkalinity does not make calcium rise. There may be many reasons for what you report, including testing errors, confusion of the dosing solutions and products, calcium additions in ways you do not realize (including tap water), water change/new salt water batch issues, etc.

 

[User1]

Adding just alkalinity does not make calcium rise. There may be many reasons for what you report, including testing errors, confusion of the dosing solutions and products, calcium additions in ways you do not realize (including tap water), water change/new salt water batch issues, etc.

Thanks. Appreciate the confirmation. I also found a few threads with regards to the Trident and low reagents which mine are and a similar issue. Replacing those now and will run through the replacement task, priming, tests, then calibration.

It probably wouldn't hurt to have a manual kit around ( I have phosphate and ALK) but not one for Cal. Or I'll run out for a cup of coffee and hit the LFS and ask them to test for me.

Thanks again. Have a great day!

 

[jaxredsoxfan]

Resurrecting an old thread, I am not sure if this is a Trident thing or something to be concerned about. It seems my Calc rises, and that has been happening for amonth or so, so I have adjusted dosing of 2 part BRS pharma (Trident controlled dosing with Neptune DOS). I decreased the dos of both sides of the 2 part but the CALC keep rising while the ALK is dropping. I turned off the CALC side of the DOS 2 days ago and it doesnt seem to be having much of an impact. Nothing was changed on the 24th or since. Am thinking this might be imbalance caused by not enough dosing of both ALK and CALC, as Randy suggests above. Would you guys recommend just bumping up both CALC and ALK with a CALC that is currently this high, or continue with increased ALK and CALC turned off. Thanks- tank is 18 month old with only 10 or so smaller corals/frags.

 

[Randy Holmes-Farley]

I've seen a surprising number of trident calcium issues, like when reagent is running out or switching to a new batch.