Alkalinity Troubles

[Kyler]

Alright boys here's what I have cookin in my tank...

My parameters are testing as follows
Calcium 380
KH 9.0
Mag 1250
No3 10-15
P04 .02-.03
Temp 73-75
Ph 7.95-8.1 (I run an apex)

For the past 3-4 weeks I have been fighting an alkalinity battle. If I dose to bring my calcium up to >420 my alkalinity jumps to 11.5-12 and sits there until I let my calcium fall below 400. I tried dosing calcium very slowly little amounts 2-3 times a day and brought up up over 10 days time and my alkalinity stayed high, I tried dosing 3 times a week and it was a little better but not much,

I do weekly consistent water changes. Water parameter on the change are
Calcium 500
Alk 8.5

I dose seachem reef calcium and Kent marine tech m magnesium

I would like to get my calcium between 420-450 and alkalinity between 8.5-9 but am open to suggestions of course.

Should I worry about the high alk or let it drop with my calcium. Is it due to what I am dosing?

Thanks for your help guys

 

[Randy Holmes-Farley]

Despite the name, Seachem Reef Calcium also boosts alkalinity. Poor product description, IMO.

Nearly any other brand of calcium supplement is mostly calcium chloride and is more suitable for your purpose.

 

[Kyler]

Thank you I had that exact suspicion.

What's interesting is even the back of my bottle says nothing of boosting Alk and my LFS told me the same but clearly it does lol

Thanks

 

[Randy Holmes-Farley]

Thank you I had that exact suspicion.

What's interesting is even the back of my bottle says nothing of boosting Alk and my LFS told me the same but clearly it does lol

Thanks

Not surprising.

Even Seachem did not realize this until I explained to them the process whereby the polygluconate may be partly or completely metabolized to provide alkalintiy. They apparently never felt the need to inform customers. Sad.

 

[GoVols]

Not surprising.

Even Seachem did not realize this until I explained to them the process whereby the polygluconate may be partly or completely metabolized to provide alkalintiy. They apparently never felt the need to inform customers. Sad.

Randy,
What about Seachem "Reef Advantage" calcium powder.
Does it have alk in it too?

 

[Randy Holmes-Farley]

Randy,
What about Seachem "Reef Advantage" calcium powder.
Does it have alk in it too?

No, its the polycluconate that's the problem. That one is OK.

Here's one place I discussed it with Seachem many years ago. IMO, it is a poorly designed (or at least poorly described) product.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=616674

 

[Randy Holmes-Farley]

Here's my discussion of calcium acetate, which is somewhat related:

The Many Methods for Supplementing Calcium and Alkalinity - REEFEDITION
https://www.reef2reef.com/blog/the-many-methods-for-supplementing-calcium-and-alkalinity

One-part balanced additive systems: Calcium Acetate

Calcium acetate is a product that has gotten relatively little publicity despite its apparent ease of use and the commercial availability to aquarists. In some ways it is similar to the combination of limewater and vinegar. When dissolved in water (fresh or salt), you have calcium ions and acetate ions. The acetate is rapidly metabolized by tank organisms to form bicarbonate, carbon dioxide, and water:

CH3CO2– (acetate) + 2 O2 → HCO3– + CO2 + H2O

This equation suggests that pH of such tanks may stay near the low end of normal, because of the excess carbon dioxide, but the practical experience of people using calcium acetate suggests that this is not a big concern.

Calcium acetate will also facilitate the growth of bacteria and the reduction of nutrients in systems, similar to that with folks dosing vinegar or vodka for that purpose. It will also facilitate conversion of nitrate to nitrogen gas (N2) in anoxic regions of live sand and rock by providing the carbon source necessary for the process. The equation below shows the process that could take place:

5 CH3CO2– (acetate) + 8 NO3– → 10 CO2 + 4 N2 + 13 OH– + H2O

One of the sources of calcium acetate available to aquarists is Salifert’s All in One (a product that also contains some strontium, amino acids, and some trace elements). It is a liquid product that can be poured directly into a tank with no immediate concerns about pH. The current version of their commercial product is 250,000-mg/L calcium acetate, so it contains the equivalent of 3,160 meq/L of alkalinity. This product sells in the US for about $45/L. Consequently, it costs about $14 per thousand meq/L of alkalinity. That price makes it very expensive for an aquarium with a large demand for calcium and alkalinity, but the zero equipment cost (unless you automate it with a dosing pump) makes it attractive for small aquaria, especially nano-reef tanks.

I have no information on the purity of the material, or the exact nature of the “trace elements” in it. Everything in the bottle will be delivered to the tank. It poses no unusual safety concerns. The upper limit to how much calcium and alkalinity can be supplied to a tank in this fashion depends on two factors. If the metabolism of acetate is rapid and the dose is very high, oxygen might be depleted. If the conversion is slow then acetate can build up in the tank (not itself a significant concern except perhaps at very high levels where it might confound an alkalinity test). Habib Sekha of Salifert has indicated that using the doses recommended on the bottle will not lead to either of these issues being problematic.

Overdosing is not expected to be an unusual problem, but if one makes significant additions in this fashion, the alkalinity will take time to show up completely in the tank because the acetate takes time to be metabolized. Consequently, I’d wait a day after adding it to measure alkalinity. Calcium measurement won’t be similarly impacted. Tank salinity will not increase over time using calcium acetate.

 

[UCedumacasion]

Does your Magnesium fluctuate, too? I had problems with an alkalinity destabilization because my magnesium was inconsistent

 

[Randy Holmes-Farley]

What sort of inconsistent magnesium? it is very slow to deplete. Anything faster than 1-2 ppm per day is test error.

 

[GoVols]

IMO, it is a poorly designed (or at least poorly described) product

+1

(lol) going to take me some time to soak your post #7 in

 

[UCedumacasion]

What sort of inconsistent magnesium? it is very slow to deplete. Anything faster than 1-2 ppm per day is test error.

I personally was having Calcium consumption in the 20-30 ppm/day (easily) in a 40 gallon aquarium so despite my testing and consistent waterchanges all my levels were dropping. I don't think that it had anything to do with inaccurate testing as I was testing with Salifert as well as Red Sea Test Kits at the time and had worked within the hobby for about 10 years at that point but at one point I had to dose:

2 part
Ca - 30ml/2x per day
Alk- 30-35ml/2x per day
Mg - 30ml/3x per week

Sr - weekly
Iodine - weekly

Aminos - twice weekly

10-15g water changes each week

I was using a bacterial dosing system (Prodibio) as well as pohls at the time

But if I didn't dose this regimen my alk would drop 3-4 dkh daily (I even spread it out over the day and dosed 10 ml every couple of hours to see if consumption changed but it didn't). I also was dosing Alkalinity more than 1 hour after dosing Calcium.

Any thoughts (also apologize for a brief hijack of the thread)

 

[UCedumacasion]

I should also note that the large dosages were distributed over an hour to avoid crazy spikes (It was already ridiculous) and testing was done more than 12 hours after dosing.

This also kept the parameters close to
Ca - 440
dkh - 9
Mg - 1300

 

[Randy Holmes-Farley]

I personally was having Calcium consumption in the 20-30 ppm/day (easily) in a 40 gallon aquarium so despite my testing and consistent waterchanges all my levels were dropping. I don't think that it had anything to do with inaccurate testing as I was testing with Salifert as well as Red Sea Test Kits at the time and had worked within the hobby for about 10 years at that point but at one point I had to dose:

2 part
Ca - 30ml/2x per day
Alk- 30-35ml/2x per day
Mg - 30ml/3x per week

Sr - weekly
Iodine - weekly

Aminos - twice weekly

10-15g water changes each week

I was using a bacterial dosing system (Prodibio) as well as pohls at the time

But if I didn't dose this regimen my alk would drop 3-4 dkh daily (I even spread it out over the day and dosed 10 ml every couple of hours to see if consumption changed but it didn't). I also was dosing Alkalinity more than 1 hour after dosing Calcium.

Any thoughts (also apologize for a brief hijack of the thread)

You mentioned inconsistent magnesium. If the magnesium was inconsistent day to day or even week to week, that would be testing error (assuming inconsistent means a substantial change like 50 ppm in a week).

Assuming you were using my DIY recipe (as sold by BRS), you were dosing enough magnesium to add 4 ppm per day. So it wouldn't be changing much day to day even with no dosing.

With a demand of 3-4 dKH per day, the proportional calcium is about 26 ppm (for 4 dKH per day) and the proportional magnesium is about 1.9 ppm per day.

The difference between this and what you report is probably the water changes you do each week, which mess with the relative demand of these things since salt mixes rarely exactly match the tank, but even if not, it would take a while to distinguish differences of a couple of ppm magnesium per day using kits that have pretty poor reproducibility/accuracy.

I don't think there are any known organisms or processes that take up a lot more magnesium per unit of alkalinity demand than used to get the above ratio, and if there was, the expected calcium demand (26 ppm per day) would actually decline. So it is not just a case that "every tank varies".

 

[UCedumacasion]

You mentioned inconsistent magnesium. If the magnesium was inconsistent day to day or even week to week, that would be testing error (assuming inconsistent means a substantial change like 50 ppm in a week).

Assuming you were using my DIY recipe (as sold by BRS), you were dosing enough magnesium to add 4 ppm per day. So it wouldn't be changing much day to day even with no dosing.

With a demand of 3-4 dKH per day, the proportional calcium is about 26 ppm (for 4 dKH per day) and the proportional magnesium is about 1.9 ppm per day.

The difference between this and what you report is probably the water changes you do each week, which mess with the relative demand of these things since salt mixes rarely exactly match the tank, but even if not, it would take a while to distinguish differences of a couple of ppm magnesium per day using kits that have pretty poor reproducibility/accuracy.

I don't think there are any known organisms or processes that take up a lot more magnesium per unit of alkalinity demand than used to get the above ratio, and if there was, the expected calcium demand (26 ppm per day) would actually decline. So it is not just a case that "every tank varies".

Thanks Randy. It always drove me nuts but looking back (as this tank was from about 7 years ago) I tested magnesium inconsistently (oftentimes on each side of a water change) and that would definitely throw all the testing off. I assume that my kits were accurate but have since been more consistent in testing of my home aquarium (I was always good with Ca and dkh but Mg was always inconsistent as it usually did remain stable).

I appreciate the given ratio. I've spent a lot of time over the years on nomenclature, taxonomy, and import/export regulations so my chemistry has gotten a little bit rusty but wanted to ask since I saw you commented.

 

[BluewaterLa]

one overlooked aspect often over looked is over dosing the tank even slightly can cause a false increase for demand on Cal, Alk when they are not being consumed more so than they are binding together OR one suppressing the other skewing our perception that More ml. needs to be dosed to keep up.
Some times we need to allow them to drop slowly or just perform a large water change to help reset a balance and figure out what the actual demand is once again.