Why Am I Burning Through So Much Alk?

Jonify

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Edit: SOLVED.

Hi there, I've got a new 13.5 gallon nano with frags (probably closer to 12 with sand and rock) in a super high CO2 environment where PH normally sits around 7.6 at about 7-8 Alk. (Adding a CO2 scrubber can get me up to about 7.7, but this is still unacceptable. You yourself (RHF) said that even at 7.8, coral growth is pretty much stagnant, and NSW doesn't generally dip to 7.8). Over the past week, based on your advice and research, I've slowly increased my alkalinity from about 7 to 12, which brings my PH to about 8.0, and this is a number I am good with. However, I'm having to dose an additional 2 dKH [Edit, now up to 3 dKH] every day just to hold alkalinity at 12 (this can't be right--I've only got about 4 small SPS frags and 4 small LPS frags!) My calcium is usually high, ranging from 480-560, so I feel like alkalinity isn't actually getting taken up that quickly--if it were, I'd see calcium being consumed at the same rate, yes?

My question is, should I keep dosing Foundation B for right now to hold alkalinity at 12 and PH at 8.0? If so, will my calcium build up over time--and is that okay? Will my coral eventually start up taking calcium too, and level out this alk-calc relationship? (And then I'd start 2-part dosing something like Tropic Marin's All for Reef?)

I've read all your articles on ReefKeeping, and for some reason, I'm not picking up what you're putting down :p Also, hope folks don't reply with "don't chase a number." While I generally agree with that, 7.6-7.7 PH is not a number I can accept, given the available research, especially with a new tank where I'm trying to grow out frags. In a year or two, I'd be fine with this coming back down to around 7.8 if I didn't want to keep pursuing growth.
 
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Spare time

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Let the calcium drop. Dose what your tank uses in a day when you get it back to your prefered levels. Also, alk drains significantly faster than calcium so that should not be dosed evenly. I have a feeling that you might be having precipitation issues. Do you dose them at the same time by any chance? Also, you will start to drain a lot of alkalinity a day in a tank that size with SPS. An auto water change system may be handy since you are burning through not just major elements, but things like iron and what not.
 

Randy Holmes-Farley

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Also, alk drains significantly faster than calcium so that should not be dosed evenly

Most two part products are designed for equal parts dosing, and take into account that alk drops faster than calcium (about 2.8 dKH for each 18-20 ppm of calcium)
 

Dkeller_nc

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Hi there, I've got a new 13.5 gallon nano with frags (probably closer to 12 with sand and rock) in a super high CO2 environment where PH normally sits around 7.6 at about 7-8 Alk. (Adding a CO2 scrubber can get me up to about 7.7, but this is still unacceptable.

As other replies implied, I'd first check to see if you're getting significant abiotic precipitation of calcium carbonate. That's fairly easy to check - simply look at your heater, and possibly dissemble a wave pump or return pump and check to see if there's a large amount of scaling (calcium carbonate) on the impeller or impeller housing. If that's the case, the next thing to check is your magnesium level. As several of Randy's articles note, the solubility of calcium and carbonate/bicarbonate in sea water is a complex result of pH, specific gravity, temperature, organic content of the water, and especially, magnesium concentration.

If you are getting significant abiotic precipitation and your magnesium level is not about 1300 ppm or so, you may want to consider dosing a magnesium chloride/magnesium sulfate solution that you can either purchase pre-made or make yourself (Randy's various 2-part DIY articles can guide you on making a mag supplement yourself).

You also may want to purchase a secondary temperature measurement device if you don't already have one. It's quite possible that an individual temp measurement device is off by 3 degrees F or more, and the higher the temp in the tank, the more strongly abiotic precipitation of calcium carbonate will occur (which is why heaters and the interiors of pumps generally show scaling first). As to which temp measurement device to consider, I find that the LifeGard Aquatics ones to be the most accurate of the relatively inexpensive devices sold to aquarists. This opinion is the result of comparing the Lifegard products to the coral-life products, Neptune's Apex probes, and several other solutions in a industrial temperature calibration device (specifically, a Fluke metrology dry-well calibrator). There's a lot of debate about what the "proper" reef tank aquarium temperature is, but in my case I typically keep my tanks at 78 deg F.

Finally, you might consider rectifying the high CO2 environment through a heat-recovery ventilation unit or other means. If for no other reason for your personal health, regardless of your reef tank.
 
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Let the calcium drop. Dose what your tank uses in a day when you get it back to your prefered levels. Also, alk drains significantly faster than calcium so that should not be dosed evenly. I have a feeling that you might be having precipitation issues. Do you dose them at the same time by any chance? Also, you will start to drain a lot of alkalinity a day in a tank that size with SPS. An auto water change system may be handy since you are burning through not just major elements, but things like iron and what not.

Thank you--I'm not dosing calcium at all, that's just being replenished at larger weekly water changes for now. When I dose alk, I don't see any precipitate unless I dose too quickly ... pumps and heater don't have any precip on them either (but I clean them same time I do water changes, so maybe it's just not happening quickly enough between water changes for me to notice. I'll consider the AWC ... have a few dosing pumps lying around not being used right now.
 
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Jonify

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Most two part products are designed for equal parts dosing, and take into account that alk drops faster than calcium (about 2.8 dKH for each 18-20 ppm of calcium)

Ah, that makes sense--thank you! Next water change when calcium levels come back closer to even, I will just implement the 2-part vs. continuing Foundation B, and keep an eye on daily calcium consumption. If calcium isn't being taken up around 18-20 ppm for 2.8 dKH, I'll assume I've got an issue.
 
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Jonify

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As other replies implied, I'd first check to see if you're getting significant abiotic precipitation of calcium carbonate. That's fairly easy to check - simply look at your heater, and possibly dissemble a wave pump or return pump and check to see if there's a large amount of scaling (calcium carbonate) on the impeller or impeller housing. If that's the case, the next thing to check is your magnesium level. As several of Randy's articles note, the solubility of calcium and carbonate/bicarbonate in sea water is a complex result of pH, specific gravity, temperature, organic content of the water, and especially, magnesium concentration.

If you are getting significant abiotic precipitation and your magnesium level is not about 1300 ppm or so, you may want to consider dosing a magnesium chloride/magnesium sulfate solution that you can either purchase pre-made or make yourself (Randy's various 2-part DIY articles can guide you on making a mag supplement yourself).

You also may want to purchase a secondary temperature measurement device if you don't already have one. It's quite possible that an individual temp measurement device is off by 3 degrees F or more, and the higher the temp in the tank, the more strongly abiotic precipitation of calcium carbonate will occur (which is why heaters and the interiors of pumps generally show scaling first). As to which temp measurement device to consider, I find that the LifeGard Aquatics ones to be the most accurate of the relatively inexpensive devices sold to aquarists. This opinion is the result of comparing the Lifegard products to the coral-life products, Neptune's Apex probes, and several other solutions in a industrial temperature calibration device (specifically, a Fluke metrology dry-well calibrator). There's a lot of debate about what the "proper" reef tank aquarium temperature is, but in my case I typically keep my tanks at 78 deg F.

Finally, you might consider rectifying the high CO2 environment through a heat-recovery ventilation unit or other means. If for no other reason for your personal health, regardless of your reef tank.

Thank you for the thoughtful response. I was considering an exchanger for the HVAC as well--thanks for bringing that up. Summers in DC are too hot to keep the windows open. There doesn't seem to be any precip, at least nothing that is building up between weekly water changes when I also clean the heater and pump. I agree though, it does sound like there would be--I'll check mag as well today and post results (admittedly, I don't track that as closely as calcium and alkalinity--eek).
 

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I would not chase ph if your tanks inhabitants are happy and healthy. I had a thriving mixed reef with a ph at 7.6 -7.7, it never got above 7.9 at its best and stayed near the bottom end. Growth was not stagnant it was very good so I am not sure where randy got this from. If your worrying about ph because of something you read rather than something your seeing that’s up to you but most any reef that’s being taken care of well should never need ph checked. I know that’s not what you want to hear.
 
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Update on magnesium, it's at 1650ppm. Had to dose another 3 dKH today just to hold it at 11.8-12 dKH.
 
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I would not chase ph if your tanks inhabitants are happy and healthy. I had a thriving mixed reef with a ph at 7.6 -7.7, it never got above 7.9 at its best and stayed near the bottom end. Growth was not stagnant it was very good so I am not sure where randy got this from. If your worrying about ph because of something you read rather than something your seeing that’s up to you but most any reef that’s being taken care of well should never need ph checked. I know that’s not what you want to hear.
I have heard this from several people--including the folks from BRS, so obviously there is merit to what you're saying. But when I look into the science, it seems nearly impossible for a coral to able to uptake enough calcium and alkalinity at PHs lower than 7.8 to thrive. For my tank, I wouldn't say there are thriving--about half are doing well (2 of the 4 SPS and 2 of the 4 LPS), the other half are not. I'm tempted to set up another tank with the same amount/type of coral and not dose anything, using just water changes to replenish elements, just to see how two tanks progress with different Alk/PH targets.
 

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Just out of curiosity have you gone through the sand and felt for any clumps of sand?
Sometimes they form out in the open but sometimes they are under the rock work.
BTW your not the only one having issue with 2 part. My water seems to be out of balance and I am still wondering why. The corals seem fine but my needed calcium dosage is greater than the ALK and I am at a loss as to why. My PO4 is low and I cannot find any precipitation so something else is bonding to the calcium. For now I am just dosing them equally and seeing where the Ca number settles at while just keeping the ALK at 8.5
 

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Do you know the corals that your struggling with to be easy to keep? I mean “don’t chase ph” was the first thing I learned in reefing. As long as the tank is cycling nutrients and elements correctly ph won’t get Low enough to be a problem, or that’s what I was taught.
 

Dkeller_nc

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By the way - If you choose, you can buy an indoor air CO2 meter for about $100. Though if your pH readings in your tank are accurate, you REALLY might not like the answer from a CO2 meter.
 
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Do you know the corals that your struggling with to be easy to keep? I mean “don’t chase ph” was the first thing I learned in reefing. As long as the tank is cycling nutrients and elements correctly ph won’t get Low enough to be a problem, or that’s what I was taught.
Interesting--now that you mention it, both of my birdsnest, my acropora, my hammer and goniastrea are fine. The ricordia, anacropora, platygyra, and chalice are all visually stressed. The chalice is nearly bleached. I believe this is from the stress of going from WWC's higher PH environments to mine, which is naturally low PH. The continuously increasing levels of dosing alkalinity to just to keep it high enough to keep PH above 7.8 probably doesn't help, I'm sure.
 
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Update, it seems the benefits of higher alk on PH was temporary--I can't keep alk stable at 11-12 (which matches the salt I'm using btw, RSCP) without having to continuously dose increasingly more every day just to hold it. At this pace I'll be pouring a whole bottle in every day--to my tiny nano! Further, the PH increase I got from bringing alk up initially (was able to get 8.0 PH at 12dKH) doesn't hold. PH just keeps decreasing gradually, even if I keep dosing to hold dKH. Right now, I'm at 7.69 PH and 10.6 dKH. I'm assuming most of the dosing is just precipitating out because the level drops back down too rapidly after I dose, and PH doesn't stay as high as it was. (Though I don't see any precipitate on pumps/heaters/glass--I DO see a light film of precipitate on the water surface 24X7 now). Calcium is at the lower end of recommended levels (380), magnesium at the higher end (1440).
 

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I looked at your tank build and the one thing that I am not seeing but maybe is hidden is some form of aeration. If your house is small and locked up all day the C02 levels will be really high. If you don't already have it I suggest a protein skimmer with the air line routed outside the house or as the least an air pump outside and the hose run into your over flow and connected to an air-stone.
Bottom line is I think your fighting high levels of indoor CO2. A canister Co2 scrubber may not be enough.
 

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Update, it seems the benefits of higher alk on PH was temporary--I can't keep alk stable at 11-12 (which matches the salt I'm using btw, RSCP) without having to continuously dose increasingly more every day just to hold it.

Raising alkalinity with a high pH additives (carbonate, or hydroxide) will have a temporary boost to pH, depending on what exactly you add. The effect can be quite high.

Raising pH with any additive will have a permanent effect of about 0.3 pH units for each doubling of alkalinity, assuming the carbon dioxide level is unchanged.
 
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Jonify

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Raising alkalinity with a high pH additives (carbonate, or hydroxide) will have a temporary boost to pH, depending on what exactly you add. The effect can be quite high.
Thanks so much for clarifying--I remember reading that in your articles, but didn't make the connection. What I had been using was Red Sea Foundation B, which is carbonate. It seemed to require a higher and higher dose each time just to keep it stable, with less of a PH raising effect each time ... I'm assuming in my case that's mostly because of increasing rates of precipitation, though I know there are other factors, including higher uptake during higher dosing. Did a water change and going to start ramping up All for Reef over a few weeks to hold Alk steady instead. Alk at 10.5, PH at 7.73.
 
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Jonify

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I looked at your tank build and the one thing that I am not seeing but maybe is hidden is some form of aeration. If your house is small and locked up all day the C02 levels will be really high. If you don't already have it I suggest a protein skimmer with the air line routed outside the house or as the least an air pump outside and the hose run into your over flow and connected to an air-stone.
Bottom line is I think your fighting high levels of indoor CO2. A canister Co2 scrubber may not be enough.
Thanks, yes I have a wave maker and a skimmer for aeration, and the skimmer air line is hooked into a recirculating CO2 scrubber, but my skimmer is pretty crap and inconsistent--can't really replace it because it's the only thing that will fit in the chamber of the Fluval.
 

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