2 Part Dosing Different Quantities

[ekandler]

I’ve been reefing for a few years now and recently I’ve been surprised at the rate my tank is consuming alkalinity compared to calcium. To keep consistent 8.5dkh and 450ppm the alkalinity is double that of the calcium. What would be the cause of this?

I’ve always wanted to try an all in one dosing solution like All-for-reef but seeing these disparities in 2 part makes me concerned to try it. Is the additional consumption of alkalinity due to my higher pH? I do run a CO2 scrubber.

 

[fishski13]

So alkalinity always drops faster than calcium just because the ratio of one to another is greater on the calcium part. You pH of 8.1 is pretty normal not high. This is a pretty normal occurring thing in reef tanks that alkalinity drops faster than calcium, so nothing to worry about besides just dosing both to keep constant

 

[Randy Holmes-Farley Verified Community Expert]

Not all two parts are designed for 1:1 dosing. How much of what are you dosing?

 

[Randy Holmes-Farley Verified Community Expert]

Hi pH does not alter the relative demand for calcium and alk except that it encourages the use by corals and by abiotic precipitation of calcium and alk in the standard proportions to form calcium carbonate.

 

[homer1475]

Took me a long time to understand dosing(many years), as I noticed the same thing. Alkalinity dropping with no change to calcium.

When I started a thread oh so many years ago back on RC, randy held my hand, and walked me through the process. It wasn't until that moment that I realized I should be dosing 1:1.

When I started dosing 1:1 my test numbers always came back within range even though by my test kits, my calcium should have been raising, but it wasn't!

If your using a product thats designed to be dose 1:1, you most certainly should be. @Randy Holmes-Farley can certainly explain it better then I.

 

[ekandler]

Not all two parts are designed for 1:1 dosing. How much of what are you dosing?

I guess that’s fair, never thought about it like that. The picture I took today shows my dosing in the past 24 hours of 30.6ml of alk and 16.8ml of calcium, using BRS brand two part.

 

[homer1475]

BRS based their recipe of Randys DIY, so it should be dosed 1:1.

 

[A_Blind_Reefer]

I had a similar issue when I first started dosing two part. Like above, Randy smacked me across the face and basically had me stop, watch the consumption while not dosing, and calculate all over again. Some things can precipitate out if dosed all at once, or not in a high flow area, etc. I would try that and see where you are. Also match the salt if you’re not already, as if it’s not the same parameters as what your trying to accomplish it will be out of whack.

 

[ekandler]

I had a similar issue when I first started dosing two part. Like above, Randy smacked me across the face and basically had me stop, watch the consumption while not dosing, and calculate all over again. Some things can precipitate out if dosed all at once, or not in a high flow area, etc. I would try that and see where you are. Also match the salt if you’re not already, as if it’s not the same parameters as what your trying to accomplish it will be out of whack.

I’m using Red Sea blue bucket which mixes to 8dkh I believe, so close to where I keep my tank to which I do intentionally. I have the DOS programmed to the Trident and it doses automatically, they don’t dose together but i don’t know exactly how to control it to dose at particular times.

 

[ekandler]

BRS based their recipe of Randys DIY, so it should be dosed 1:1.

So if my two part is designed to be doses 1:1 and my tank isn’t consuming equal amounts, do I keep dosing what is required per my Trident testing or do it ignore the test results and dose 1:1? And if I dose 1:1, do I pick dosing quantity for both additives based on the alkalinity test results or calcium test results?

Adding to this, if these additives are meant to be does 1:1 regardless of test results, what is the benefit of 2 part dosing vs all-for-reef? I always thought it was of benefit to separate your additives to control them separately, but if the goal is to avoid dosing inequal amounts, why not just use all-for-reef? (Aside from cost)

 

[A_Blind_Reefer]

I’m using Red Sea blue bucket which mixes to 8dkh I believe, so close to where I keep my tank to which I do intentionally. I have the DOS programmed to the Trident and it doses automatically, they don’t dose together but i don’t know exactly how to control it to dose at particular times.

Out of curiosity, have you checked your trident results against another test kit? I’m curious if there are any other factors that coincide with the recent changes in consumption as well. It seems very odd that every thing has been fine for a few years and just out of the blue, something changed for no apparent reason.

 

[homer1475]

The problem is the very small drop in calcium that our test kits do not pick up, in relation to the large drop in Alkalinity (Think it's like 20ppm to 1dkh @Randy Holmes-Farley can correct me if I'm wrong).

Every test kit on the market has a margin of error, what your seeing is a very small drop in calcium, combined with the margin of error. See where you might not see a drop in calcium until there is a large one?

Yes they are designed to be dosed 1:1 but there are instances where you may not need it.

Advantages over A4R, no idea never used it. Deemed it too expensive for my consumption. I prefer calcium chloride, and baking soda for my 2 part(randys diy 2 part).

EDIT:
That 2 part is designed to be based off Alk consumption. So if your dosing say 50ml of alk, you dose 50ml of calcium. It's an ionic balance thing that @Randy Holmes-Farley could explain far better then I.

 

[A_Blind_Reefer]

So if my two part is designed to be doses 1:1 and my tank isn’t consuming equal amounts, do I keep dosing what is required per my Trident testing or do it ignore the test results and dose 1:1? And if I dose 1:1, do I pick dosing quantity for both additives based on the alkalinity test results or calcium test results?

Adding to this, if these additives are meant to be does 1:1 regardless of test results, what is the benefit of 2 part dosing vs all-for-reef? I always thought it was of benefit to separate your additives to control them separately, but if the goal is to avoid dosing inequal amounts, why not just use all-for-reef? (Aside from cost)

I’m not so sure that I personally would have the trident control the dosing. In theory it’s a great idea, in practice I have not heard outstanding results. Myself I would use it to monitor trends and always back it up with a manual test to confirm dosage amounts. But, that’s just me.

 

[ekandler]

Out of curiosity, have you checked your trident results against another test kit? I’m curious if there are any other factors that coincide with the recent changes in consumption as well. It seems very odd that every thing has been fine for a few years and just out of the blue, something changed for no apparent reason.

I calibrate it with every reagent refill like I’m supposed to. I’ve checked it against Hanna checkers in the past but not recently, and it was accurate when I did.

It’s not that it’s changed recently, it’s that I can now monitor it with the DOS. my reef has been running for a few years with BRS dosing but didn’t have the Trident/DOS that whole time, maybe in the past 9 months. Before then I can’t say exactly what the dosing quantities were, but now I’ve just started paying more attention and noticed the disparity.

 

[ekandler]

I’m not so sure that I personally would have the trident control the dosing. In theory it’s a great idea, in practice I have not heard outstanding results. Myself I would use it to monitor trends and always back it up with a manual test to confirm dosage amounts. But, that’s just me.

I’ve never had any issues with it. I calibrate the trident with every reagent change as is recommended and I’ve checked it against a Hanna checker when I’ve had reason to doubt the readings, but it’s never shown an inaccuracy. I also have been ICP testing more regularly lately since i started dosing trace elements and the mag/calc values always match my Trident tested values.

 

[ekandler]

The problem is the very small drop in calcium that our test kits do not pick up, in relation to the large drop in Alkalinity (Think it's like 20ppm to 1dkh @Randy Holmes-Farley can correct me if I'm wrong).

Every test kit on the market has a margin of error, what your seeing is a very small drop in calcium, combined with the margin of error. See where you might not see a drop in calcium until there is a large one?

Yes they are designed to be dosed 1:1 but there are instances where you may not need it.

Advantages over A4R, no idea never used it. Deemed it too expensive for my consumption. I prefer calcium chloride, and baking soda for my 2 part(randys diy 2 part).

EDIT:
That 2 part is designed to be based off Alk consumption. So if your dosing say 50ml of alk, you dose 50ml of calcium. It's an ionic balance thing that @Randy Holmes-Farley could explain far better then I.

@Randy Holmes-Farley if I could get the explanation on the ionic balance that’d be great.

Seems like the general consensus is I should be programming my calcium dosage to match that of my alkalinity dosage regardless of the calcium test results. If that’s the correct thing to do, I can certainly do that.

still curious to know, if that’s the intent behind 2 part, why all-for-reef isn’t preferred over 2 part aside from the cost associated.

 

[A_Blind_Reefer]

I calibrate it with every reagent refill like I’m supposed to. I’ve checked it against Hanna checkers in the past but not recently, and it was accurate when I did.

It’s not that it’s changed recently, it’s that I can now monitor it with the DOS. my reef has been running for a few years with BRS dosing but didn’t have the Trident/DOS that whole time, maybe in the past 9 months. Before then I can’t say exactly what the dosing quantities were, but now I’ve just started paying more attention and noticed the disparity.

It’s not that they’re not accurate. I believe they are great. It’s just things can happen, tube gets pinched or clogged, needle issues, etc. I’ve heard, but that doesn’t mean anything, that these things don’t happen often but when they do, it can really cause an issue with an overdose. Again, that’s just me being worried.

 

[homer1475]

You can make small adjustments with 2 part. just think of a WC, and how that can throw the dosing off if say you keep your ALK at 9 and your WC water is 7.

 

[SPS2020]

A great article to understand why the demand may not balance by our resident Reef Chemist.

When Do Calcium and Alkalinity Demand Not Exactly Balance?

 

[Randy Holmes-Farley Verified Community Expert]

I guess that’s fair, never thought about it like that. The picture I took today shows my dosing in the past 24 hours of 30.6ml of alk and 16.8ml of calcium, using BRS brand two part.

There are two recipes of mine that BRS uses, and one is exactly half as potent as the other. So if you mixed the two recipes up somehow, that could explain your result.

So would rising nitrate that consumes alk and not calcium, or water changes with a mix that is relatively enriched in calcium relative to your tank water.

So would top off with well or tap water thst contained calcium. That is why I asked about well water.

what is your tank volume? That will help to understand the magnitude of the effect you report.