Poll: Alkalinity - Daily Demand

[leorii2000]

I use a home made baking soda ash mix. Can’t tell exactly how much. But I add some every couple of days keeping all around 8 dkH in a mixed 220

 

[Wiskey]

I've found that the higher you crank it, the higher the demand becomes. For the last year my mixed reef has been on hands off mode. The alk has been around 6.5, CA was low as well between 380 and 400, but I was using a Kalk reactor to add some Alk and CA to the tank so I just let it ride.

Recently I added a chiller (owning one and having it properly installed outside has been a dream of mine since about 2003) and I shut down all the fans. This reduced evaporation and humidity a great deal (Awesome!) but I knew it would make Kalk less effective, so I bought a dosing pump and made the classic RHF 2 part low PH formula. Now I'm keeping Alk around 8 and growth has naturally increased to match. Now I'm at dosing 60 ML per day, but this is increasing every week as my corals react to the increased Alk/CA availability.

I'm now going to take a different tact. I'm just going to dose 1.1 dkh per day and let the value settle where it may, much like I did with the Kalk. Instead of striving for 8.0 dkh, I'm just going to up the dosing if it gets below 6.8. Likewise with CA, it's been shown that growth is stunted under 380 so I will keep them balanced unless CA drifts below say 390.

Whiskey

 

[Orm Embar]

I'm a lowbie - my current estimated dKH consumption is roughly 0.31, possibly as high as 0.55 (I'm tweaking my doser) against a background alk of 9 dKH. Tank with zoas, softies/shrooms, and some LPS with 1 Cyphastrea frag feeling all alone.

Frighteningly, I was doing some napkin math and almost cried when I saw how much I'm paying for my current setup by the gallon (Kamoer x1 doser with Tropic Marin's All-For-Reef):

1 gallon of baked baking soda and bulk calcium chloride: darn low
1 gallon each of CaCl2 and Na2CO3 from BRS: roughly $5?
1 gallon of powdered CarboCalcium which I think is roughly equipotent to sodium carbonate: roughly $12
1 gallon of All-For-Reef (or roughly premixed CarboCalcium as a liquid), assuming 4 L = 1 gallon (I'm lazy): $105-120?!?!?!

In order to make myself feel better:

Dosing Tropic Marin's K+ and A- elements brings the per gallon cost up to roughly $80-100 with a base of powdered CarboCalcium, so apparently the vast majority of the cost is the trace elements.

43 gallon system
-at 10 mL/day of All-For-Reef (more napkin math), that's a $30 liter bottle over 3.3 months, or about $10/month. If I'm really at 15 mL/day consumption, then that's a $30 bottle in 2 months, or $15/month. That's a much easier pill to swallow!

I wonder if partial water changes would be cheaper; 200 gallons of Fritz red bucket - $80 (LFS estimate); assuming a 10% water change weekly is enough to keep magnesium and trace elements at steady state, that's 4 gallons/week x ($80/200 gallons) x (52 weeks/1 year) = $80/year. Actually, that's about what I get for Tropic Marin's trace elements line. Huh . . .

I have no idea if other companies make significantly cheaper trace elements with similar quality, but that's a loaded question!

 

[Ferrell]

I haven’t checked my usage in about a year butI have a lightly stocked 75 gal with 20 gallon sump. ~80 gallons of h2o.
Currently dose 40 ml soda ash and 40 ml calcium + dose about 300 ml kalk daily. Stays about 8.4-8.6 dkh

Edit:::>Using the brs calculator my doseage equates to about 0.7 dkh daily

 

[vanpire]

Wouldn't the poll make more sense with aquarium size? Someone with 1dKH consumption in a 30 gallon tank is not the same as another one with a 1dKH consumption in a 300 gallon tank.

 

[12gallonsofhex]

I have a 20 gal long (used to be 12 hex) that has 4 lps frags, a mushroom, and 4 no name zoa mini colonies. It is using about .2 dkh per day. My corals seem to like between 8 and 8.5.

 

[o2manyfish]

Thanks to my Alkatronic testing hourly I can actually track this. With 1300g during the day when the sun is out and lighting the outdoor frag tank the alkalinity will drop .5 dkh per hour. The Dastaco keeps things leveled out.

Dave B

 

[GoVols]

(lol)
This thread is so old, that I had to change (vote) from .6-1.0 to 2.o-2.5

11o gallon bare bottom mixed reef / 80 gallons after displacement.

Holding .35ppt / alk at 9.0 dkh

2 stage GEO cal reactor / monitored and controlled with Alkatronic (V3)

Salifet alk kit as crosscheck to Alkatronic.

 

[vanpire]

Thanks to my Alkatronic testing hourly I can actually track this. With 1300g during the day when the sun is out and lighting the outdoor frag tank the alkalinity will drop .5 dkh per hour. The Dastaco keeps things leveled out.

Dave B

Are the drops pretty even thoughout the day and all day long? Some people are saying that the corals only calcify for a several hours per day instead of throughout the day. What have u found? What par. is your frag tank? Do u have a build thread for this? I am very interested in what u r doing.

 

[Jet915]

I'm up to about 50 ml of BRS alk a day to maintain a dkh of 7 in a 100 gallon mixed reef. I started 2 part dosing about 3 months ago dosing 30 ml of BRS alk...

 

[User1]

I didn't vote because I really didn't know what my values are. Every time I test is it usually after a water change. Stupid me. Anyway I did have a follow up question after reading through the tread and looking at the poll.

Please keep in mind that my upgrade is only 1 1/2 into maturing so not a lot of corals as I start slower than most I guess. Anyway is my assumption correct in that the corals that I do have in there should be consuming the various alk, cal, and mag plus other elements daily?

So today if my Alk reading 8.23 should I expect it to be lower tomorrow by some amount? And the poll is what you are asking, what that amount is or what we think? Assuming my tank is consuming it because I see growth so will be interesting to see if it does decrease. That way I would know if or when I need to start dosing something.

Thanks. Thread caught my eye and I just wanted to make sure I understood what should happen typically. I'm one of those lazy reefers who do not test regularly but now that the trident is running I'd like to pay a bit more attention.

 

[erk]

My tank uses about 1dKH/per day, but it is a mostly softie tank and the hard corals are not doing particularly well.

 

[Drewbacca]

I wouldn't pick an optimal alkalinity target based on pH effects as a primary consideration.

That said, here's my discussion on alkalinity and why one might pick different values:

Optimal Parameters for a Coral Reef Aquarium: By Randy Holmes-Farley
https://www.reef2reef.com/forums/re...-coral-reef-aquarium-randy-holmes-farley.html

Alkalinity

Like calcium, many corals also use "alkalinity" to form their skeletons, which are composed primarily of calcium carbonate. It is generally believed that corals take up bicarbonate, convert it into carbonate, and then use that carbonate to form calcium carbonate skeletons. That conversion process is shown as:

HCO3- → CO3-- + H+

Bicarbonate → Carbonate + proton (which is released from the coral)

To ensure that corals have an adequate supply of bicarbonate for calcification, aquarists could just measure bicarbonate directly. Designing a test kit for bicarbonate, however, is somewhat more complicated than for alkalinity. Consequently, the use of alkalinity as a surrogate measure for bicarbonate is deeply entrenched in the reef aquarium hobby.

So, what is alkalinity? Alkalinity in a marine aquarium is simply a measure of the amount of acid (H+) required to reduce the pH to about 4.5, where all bicarbonate is converted into carbonic acid as follows:

HCO3- + H+ → H2CO3

The amount of acid needed is equal to the amount of bicarbonate present, so when performing an alkalinity titration with a test kit, you are “counting†the number of bicarbonate ions present. It is not, however, quite that simple since some other ions also take up acid during the titration. Both borate and carbonate also contribute to the measurement of alkalinity, but the bicarbonate dominates these other ions since they are generally lower in concentration than bicarbonate. So knowing the total alkalinity is akin to, but not exactly the same as, knowing how much bicarbonate is available to corals. In any case, total alkalinity is the standard that aquarists use for this purpose.

Unlike the calcium concentration, it is widely believed that certain organisms calcify more quickly at alkalinity levels higher than those in normal seawater. This result has also been demonstrated in the scientific literature, which has shown that adding bicarbonate to seawater increases the rate of calcification in some corals. Uptake of bicarbonate can consequently become rate limiting in many corals. This may be partly due to the fact that the external bicarbonate concentration is not large to begin with (relative to, for example, the calcium concentration, which is effectively about 5 times higher).

For these reasons, alkalinity maintenance is a critical aspect of coral reef aquarium husbandry. In the absence of supplementation, alkalinity will rapidly drop as corals use up much of what is present in seawater. Water changes are not usually sufficient to maintain alkalinity unless there is very little calcification taking place. Most reef aquarists try to maintain alkalinity at levels at or slightly above those of normal seawater, although exactly what levels different aquarists target depends a bit on the goals of their aquaria.

Interestingly, because some corals may calcify faster at higher alkalinity levels, and because the abiotic (nonbiological) precipitation of calcium carbonate on heaters and pumps also rises as alkalinity rises, the demand for alkalinity (and calcium) rises as the alkalinity rises. So an aquarist generally must dose more calcium and alkalinity EVERY DAY to maintain a higher alkalinity (say, 11 dKH) than to maintain 7 dKH. It is not just a one-time boost that is needed to make up that difference. In fact, calcification gets so slow as the alkalinity drops below 6 dKH that reef aquaria rarely get much below that point, even with no dosing: natural calcification has nearly stopped at that level.

In general, I suggest that aquarists maintain alkalinity between about 7-11 dKH (2.5 and 4 meq/L; 125-200 ppm CaCO3 equivalents). Many aquarists growing SPS corals and using Ultra Low Nutrient Systems (ULNS) have found that the corals suffer from “burnt tips†if the alkalinity is too high or changes too much. It is not at all clear why this is the case, but such aquaria are better served by alkalinity in the 7-8 dKH range.
As mentioned above, alkalinity levels above those in natural seawater increase the abiotic precipitation of calcium carbonate on warm objects such as heaters and pump impellers, or sometimes even in sand beds. This precipitation not only wastes calcium and alkalinity that aquarists are carefully adding, but it also increases equipment maintenance requirements and can “damage†a sand bed, hardening it into a chunk of limestone. When elevated alkalinity is driving this precipitation, it can also depress the calcium level. An excessively high alkalinity level can therefore create undesirable consequences.

I suggest that aquarists use a balanced calcium and alkalinity additive system of some sort for routine maintenance. The most popular of these balanced methods include limewater (kalkwasser), calcium carbonate/carbon dioxide reactors, and the two-part/three part additive systems.

For rapid alkalinity corrections, aquarists can simply use baking soda (sodium bicarbonate) or washing soda (sodium carbonate; baked baking soda) to good effect. The latter raises pH as well as alkalinity while the former has a very small pH lowering effect. Mixtures can also be used, and are what many hobby chemical supply companies sell as “buffersâ€. Most often, sodium carbonate is preferred, however, since most tanks can be helped by a pH boost.

Sincredinle info, thank you..I have yet to figure out why my sanbed has formed into rock in the corner and clumping on too everywhrecelse, the high dkh of thecredxsea salt I used and maintaining 9 dkh...had to be it...im trying to keep it at 8bnow but it wants to statcatc7.5 with my current maxed out concentration of kalk...so I might just let it stay there. Do you have any suggestions on how to get the limestone to releasecfrom my glass?(exact size/dimensions of a womans hand) and closest sand/.area to return nozzle. Avg..440 cal 1500mag 0-5 nit 0.00 -0.05 phos 8.1 ph

 

[madweazl]

Our 75g is using just a hair over 2.0 dKh per day now.

 

[MichaelClark55]

My daily is 1.5 I stay stable w 60 mls a day to keep 9.8 in a 125 heavy mixed

 

[Mrx7899]

220 total water volume the tank uses a little over 1 dkh a day and I keep it around 7.5 dkh.

 

[rsumner]

I decided to jump-in and vote on this one myself (despite this being a really old thread) due to my constant worry that I'm dosing too much.

I run an Apex Triton having it test my Alk every hour so I can see how/if there are swings throughout the day. Right now, I'm dosing about 2.8 dKH/day with about 13ppm calcium consumption. I dose every hour on the hour throughout the day and do it very slowly. My hourly dosing is around 0.126 dKH to maintain my dKH around 8.6.

I have had, what I believe to be, ionic imbalances in the past causing major precipitation (enough to where my pumps seized), so I'm always worried that my tests are off and I'm overdosing. I don't understand the chemistry behind this so don't ask me to explain it, but when my Alk consumption was this high in the past, no matter how much I would dose, I would have little impact.

I'm hoping the higher Alk consumption at this point is a sign of my 2.5yr old system finally showing signs of life and growth.

 

[Sirspeedy77]

I decided to jump-in and vote on this one myself (despite this being a really old thread) due to my constant worry that I'm dosing too much.

I run an Apex Triton having it test my Alk every hour so I can see how/if there are swings throughout the day. Right now, I'm dosing about 2.8 dKH/day with about 13ppm calcium consumption. I dose every hour on the hour throughout the day and do it very slowly. My hourly dosing is around 0.126 dKH to maintain my dKH around 8.6.

I have had, what I believe to be, ionic imbalances in the past causing major precipitation (enough to where my pumps seized), so I'm always worried that my tests are off and I'm overdosing. I don't understand the chemistry behind this so don't ask me to explain it, but when my Alk consumption was this high in the past, no matter how much I would dose, I would have little impact.

I'm hoping the higher Alk consumption at this point is a sign of my 2.5yr old system finally showing signs of life and growth.

I’m learning this too, as I’ve come to understand if magnesium is low precipitate will occur.

 

[Saltyanimals]

Old thread, but I'll keep it going.

Curious about the consumption on larger tanks. Let's say for example that your consumption is 2 dKH daily. If you were to transplant the same livestock as a whole to a take twice as large in water volume, if the consumption would reduce. i.e. more alk in the water volume per same consumption.

Trying to understand why I'm dosing so much on a smaller 65G tank compared to some of you big tank guys.

 

[Cadroved]

how much it is okay to let your alkalinity drop currently I have a 10 gallon and it drop 1 dkh every 3-4 days is it okay to let it drop that much before dosing? I don't have an auto dozer right now but I am looking in to it