Dose or no dose for Lps and Softies

saltyfilmfolks · Sep 22, 2017

Yup. Dose evenly. In most cases it's not a problem.

What product are you using?

Chiefmaster30 · Sep 22, 2017

I'm not comprehending dosing even. Right now if my cal is at 450 alk is 11.5 and mag is 1350 which is what my goal is per red seas accelerated growth program. When do I dose? And how much?

Chiefmaster30 · Sep 22, 2017

I'm using brs 2 part.

Randy Holmes-Farley · Sep 22, 2017

Start with equal parts dosing and then adjust the calcium dose when, and if, after a few weeks, you determine the dose is too high or too low.

Calcium changes much more slowly, on a percentage basis, than does alkalinity, so takes a lot longer to nail down an exact dose. Equal parts should be pretty close the the actual demand, unless water changes mess with it.

Chiefmaster30 · Sep 22, 2017

For example: my alkalinity drops from 11.5 to 11.1ish daily. So when I get ready to dose manually tonight to dose my alk and raise it back to 11.5 whatever the reef calculator says on brs to use to bring it back to 11.5 I dose the same amount of cal or??? Please help! Apparently I've been chasing numbers for 2 weeks.

Randy Holmes-Farley · Sep 22, 2017

Chiefmaster30 said:
I'm not comprehending dosing even. Right now if my cal is at 450 alk is 11.5 and mag is 1350 which is what my goal is per red seas accelerated growth program. When do I dose? And how much?

You dose nothing. Everything is plenty high.

Well, unless your goal is higher than 11.5 dKH, which, IMO, is not needed. if it is, dose equal parts to your goal.

Chiefmaster30 · Sep 22, 2017

But it drops to 11.1 daily on alk. Do I not dose alk to get it back to 11.5

Randy Holmes-Farley · Sep 22, 2017

Chiefmaster30 said:
But it drops to 11.1 daily on alk. Do I not dose alk to get it back to 11.5

Only if you want it that high (I recommend 7-11 dKH), and if the alk is dropping, so is the calcium. You just can't easily detect the small calcium change associated with a 0.4 dKH alk drop.

Chiefmaster30 · Sep 22, 2017

The reason I was shooting for 11.5 is I was trying to follow red sea's rcp and it calls for that.

rkpetersen · Sep 22, 2017

Chiefmaster30 said:
I'm still trying to get my tanks consumption with the big 3. Can anyone tell me....
1. Am I supposed to be dosing equal amounts of 2 part?
2. I've got my alk consumption down to a daily dose of around 43ml. Cal I haven't figured out yet. Last week in 7 days my tank went from 450-400ppm. I dived that x 7 correct? Which using calculator on Red Sea with a 150 gallon water volume would be 767.3ml of cal solution. Do I divide that by 7 to get my daily dose? Thanks in advance!
3. Or am I going in the wrong direction with this? If it's supposed to be dosed in equal parts I'm way off.

I'm new here but I bet this question or questions like it come up all the time! I have personally pondered calcium/alkalinity dosing for hours on end, as the recommendations and calculations on bottles and at websites failed to have any basis in my reality. My aquarium's very first extinction event was due to me chasing calc and alk all over the place, with my apex registering its dismay at my shenanigans.

Anyway, here's a few things -

1) Don't trust that those numbers you're basing ALL your dosing decisions on are so precise. They aren't. Sometimes they really aren't. If you do the math and then expect it to repeat the next week, or the next, you'll just get frustrated. Trends are what matter. Well, that, and using the best available hobbyist test kits and sending an occasional sample to Triton wouldn't hurt either (do your own tests at the same time and record for comparison later).

2) I was told that two part is designed to be dosed in equal amounts. For example, I use Reef Fusion 1 & 2 because that's what my lfs uses, and that's what they suggested. But it actually doesn't make sense. You may be adding calcium and carbonate/bicarbonate to your system in equimolar amounts, but their removal from your water definitely isn't restrained in the same fashion. Calcium leaves drop because of reef-building deposition or inorganic precipitation, perhaps a few other minor effects I'm not thinking of at the moment. Of course CO3/HCO3 are used up by the same process. But unlike calcium, carbonate/bicarbonate is ALSO in constant equilibrium with carbon dioxide dissolved in your water and in the air adjacent to your water, which can create alk fluctuations that are all over the place and will definitely not always follow the 'rules'. For example, you may know that it is possible to scrub CO2 from the air that your skimmer uses, with a CO2 scrubber cannister. Some people do this to raise their tank's pH, and it does work, at least in the short term. If you use an efficient CO2 scrubber, this will actually pull CO2 out of your tank water and into the skimmer's exhaust air. BUT, the carbonate in your aquarium now partially converts to CO2, re-equilibrating, and then THAT CO2 gets stripped by your skimmer, and so on, and the next time you check your alk, it's dropped by 2 whole dKH!!! I've done this because I thought my pH was too low; it was a bad idea. Don't do it.

Anyway, you don't necessarily have to dose equivalent amounts of two-part. That's just my opinion, based on basic science and virtually no experience!

3) Are you using a doser? If not, for diety's sake man, get a doser! Or two, because you'll probably want another at some point. Especially if you've got a relatively heavy bioload for your tank size. It just makes everything much less stressful, for both you and the critters. For better or worse, I'm hooked on Apex, and my two-part DOS module dispenses Reef Fusion 2 at 0.8 ml every 18 minutes. You just can't get that granular and smooth with hand dosing.

rkpetersen · Sep 22, 2017

Randy Holmes-Farley · Sep 22, 2017

Chiefmaster30 said:
The reason I was shooting for 11.5 is I was trying to follow red sea's rcp and it calls for that.

FWIW, VERY FEW reefers on this forum specifically target levels above 11 dKH.

It is an OK recipe for an SPS tank IF your primary goal is fast growth (as opposed to coloration), but you need to be certain nutrients do not get too low to support that growth or you risk burnt tips. It will lead to faster precipitation on pumps and such than lower alk tanks.

rkpetersen · Sep 22, 2017

The amount of Reef Fusion 2 I'd have to be dosing to keep my tank at an alk of 11.5 would be insane. And as things grow, it would just keep getting harder keeping it up there.

Randy Holmes-Farley · Sep 22, 2017

rkpetersen said:
2) I was told that two part is designed to be dosed in equal amounts. For example, I use Reef Fusion 1 & 2 because that's what my lfs uses, and that's what they suggested. But it actually doesn't make sense. You may be adding calcium and carbonate/bicarbonate to your system in equimolar amounts, but their removal from your water definitely isn't restrained in the same fashion. Calcium leaves drop because of reef-building deposition or inorganic precipitation, perhaps a few other minor effects I'm not thinking of at the moment. Of course CO3/HCO3 are used up by the same process. But unlike calcium, carbonate/bicarbonate is ALSO in constant equilibrium with carbon dioxide dissolved in your water and in the air adjacent to your water, which can create alk fluctuations that are all over the place and will definitely not always follow the 'rules'. For example, you may know that it is possible to scrub CO2 from the air that your skimmer uses, with a CO2 scrubber cannister. Some people do this to raise their tank's pH, and it does work, at least in the short term. If you use an efficient CO2 scrubber, this will actually pull CO2 out of your tank water and into the skimmer's exhaust air. BUT, the carbonate in your aquarium now partially converts to CO2, re-equilibrating, and then THAT CO2 gets stripped by your skimmer, and so on, and the next time you check your alk, it's dropped by 2 whole dKH!!! I've done this because I thought my pH was too low; it was a bad idea. Don't do it.
.

Sorry, but it does make very good sense to dose equally and much of your argument is, simply, incorrect. Changing the CO2 level in an aquarium has ZERO impact on total alkalinity. That is not any sort of issue or concern. I explain the chemistry of why later in this post.

The reason this bothers me so much, and I post on it so often, is that folks are throwing away the beauty of a two part, which avoids the roller coaster of rising and falling calcium and alkalinity that comes from using too short of an assessment period coupled with test kits of variable accuracy/reproducibility to constantly jigger the amounts dosed. Folks that stick with equal parts, or close to equal parts, to maintain alkalinity will at worst, see a very slow drift up or down in calcium, and they can slowly adjust the dose from equal to slightly off if needed. Not adjsuting every 2 days because they mistakenly think calcium jump up or down 50 ppm since yesterday.

The main thing that messes with the ratio needed to dose are water changes with a mix that does not match the tank. Sure, if that is the reason you need to dose a mismatch, then it is fine. But it is not the case that "every tank varies". The true demand is quite close to balanced. The other minor issues are covered in the article below, but would rarely be a reason one would see a mismatch in the short term (rather than the long term).

It is remarkable how many people insist they "need" to dose independently, when most of the folks using CaCO3/CO2 reactors do not agitate over that need. Why? because they can't, in part, but also be cause they do not need to. So why do so many folks "need to" when using a different method that supplies calcium and alkalinity in the same ratio? I think it says a lot about the psychology of reefers: if they can jigger it because they think they might get an improvement, they will.

Why CO2 has no impact on Alkalinity

There are several facts about total alkalinity that follow directly from the definition. Unfortunately, some of these have been misunderstood by some hobby authors.

One of these facts is termed The Principle of Conservation of Alkalinity by Pankow ("Aquatic Chemistry Concepts", 1991). He shows mathematically that the total alkalinity of a sample CANNOT be changed by adding or subtracting CO2. Unfortunately, there is an article available on line, which claims otherwise, and encourages people to "lower alkalinity" by adding CO2 in the form of seltzer water. This is simply incorrect.

Forgetting the math for the moment, it is easy to see how this must be the case. If carbonic acid is added to any aqueous sample with a measurable alkalinity, what can happen?

Well, the carbonic acid can release protons by reversing equations 1 and 2:

(5) H2CO3 ==> H+ + HCO3-

(6) HCO3- ==> H+ + CO3--

These protons can go on to reduce alkalinity by combining with something that is in the sample that provides alkalinity (carbonate, bicarbonate, borate, phosphate, etc). However, for every proton that leaves the carbonic acid and reduces alkalinity, a new bicarbonate or carbonate ion is formed that adds to alkalinity, and the net change in total alkalinity is exactly zero. The pH will change, and the speciation of the things contributing to alkalinity will change, but not the total alkalinity.

This has more on demand imbalances, real and imagined:

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

rkpetersen · Sep 22, 2017

Randy Holmes-Farley said:
S
(6) HCO3- ==> H+ + CO3--

These protons can go on to reduce alkalinity by combining with something that is in the sample that provides alkalinity (carbonate, bicarbonate, borate, phosphate, etc). However, for every proton that leaves the carbonic acid and reduces alkalinity, a new bicarbonate or carbonate ion is formed that adds to alkalinity, and the net change in total alkalinity is exactly zero. The pH will change, and the speciation of the things contributing to alkalinity will change, but not the total alkalinity.

Good point. The presence of a highly buffered environment makes the difference. In unbuffered freshwater, the H+ would just combine with OH- and the pH would drop.

However, the equation and consideration above isn't exactly what I've thinking off, although it's a factor. The equation I'm thinking of is:

CO2 (aq) + H2O « H2CO3

Which regulates the equilibrium of bicarbonate (as carbonic acid) with dissolve CO2 subsequently lost to air. There may be more variance in this parameter between setups and even with one setup at different times. Factors like tank size and depth, lid or no lid, air circulation, sump design, skimmer size and design, in-tank dead spots, etc etc etc come into consideration. When CO2 leaves to the air, possibly due to some temporary disequilibrium either induced or accidental, it will rarely come back by that route. In that case, total alk will have to drop and the deficit made up. We already know this is possible when done intentionally with a CO2 scrubber. Given the vast array of different aquarium setups, I'm inclined to believe it can happen accidentally as well.

Randy Holmes-Farley · Sep 22, 2017

rkpetersen said:
Good point. The presence of a highly buffered environment makes the difference. In unbuffered freshwater, the H+ would just combine with OH- and the pH would drop.

However, the equation and consideration above isn't exactly what I've thinking off, although it's a factor. The equation I'm thinking of is:

CO2 (aq) + H2O « H2CO3

Which regulates the equilibrium of bicarbonate (as carbonic acid) with dissolve CO2 subsequently lost to air. There may be more variance in this parameter between setups and even with one setup at different times. Factors like tank size and depth, lid or no lid, air circulation, sump design, skimmer size and design, in-tank dead spots, etc etc etc come into consideration. When CO2 leaves to the air, possibly due to some temporary disequilibrium either induced or accidental, it will rarely come back by that route. In that case, total alk will have to drop and the deficit made up. We already know this is possible when done intentionally with a CO2 scrubber. Given the vast array of different aquarium setups, I'm inclined to believe it can happen accidentally as well.

Sorry, you are misunderstanding the chemistry (as have some very big name hobby authors in the past).

Adding or subtracting CO2 from seawater or freshwater has zero impact on alkalinity. There is no uncertainty here. It is, almost by definition, ZERO impact. This can be taken straight from water chemistry textbooks. It's not my invention.

Let me try explaining it a different way...

Dissolving CO2 adds carbonic acid. Yes, that carbonic acid can dissociate to produce both bicarbonate and carbonate.

But to do so, it releases H+, and in EXACTLY the same amount as the bicarbonate (and twice the carbonate). Thus it exactly offsets the carbon forms.

What does that H+ do? It really doesn't matter since H+ is part of the total alkalinity (TA) equation:

TA = [HCO3-] + 2[CO3--] + [B(OH)4-] + [OH-] + [Si(OH)3O-] + [MgOH+] + [HPO4--] + 2[PO4---] - [H+]

but in actuality, most of the H+ released will combine with other carbonate and bicarbonate ions, converting them into bicarbonate and carbonic acid again.

So it has no impact on total alkalinity.

rkpetersen · Sep 22, 2017

Carbonate/bicarbonate hardness vs total alkalinity.

Randy Holmes-Farley · Sep 22, 2017

rkpetersen said:
Carbonate/bicarbonate hardness vs total alkalinity.

All of the kits and commercial devices that we use measure total alkalinity (with the exception of a Seachem kit that tries to measure borate alkalinity and then subtract it from total alk to get carbonate alk; and the not yet released Mindstream). Also, the contribution of actual H+ and OH- to total alkalinity at any pH that we actually attain in reef aquaria is never significant except in theory to say that it sums to exactly zero on adding or subtracting CO2).

Let me give an alternative explanation for what you observed when you scrubbed out CO2 and found the alk to decline. That can and will happen because both coral/coralline uptake of calcium and alkalinity and abiotic precipitation of calcium carbonate rises as the pH rises.

The scrubbing elevated the pH, increased the demand, and you observed the alk to decline.

If you raise the pH that way (or others), you often need to increase dosing of calcium and alkalinity for this reason.

saltyfilmfolks · Sep 22, 2017

^^^^^yup.

For the OP this all means calculate the dose by testing over weeks. And dose evenly.

Calculate and then Under dose. Over the course of weeks ("literally)slowly increase the dose. Maybe only once a week if not more , and this Esp depends on your water change schedule.

You may see slight unevenness depending on the salt mix, but still dose evenly for a long period of time before adjusting to an unbalanced dosing regumine. It'll take time for that to become appearant.

It took me over two months for me to be happy with my dosage amount.

With the last product I used (my first time dosing) I was slightly overdosing my tanks desired levels and I took an additional month to let it self correct. Made it over three months total to find the right dose.