Calcium consumption higher than Alkalinity consumption

[Randy Holmes-Farley]

A higher portion of calcium to soda ash.

I am not dosing anything else to my tank besides your DIY recipe + part c. The only scenario (checking now) I can see is possibly the calcium precipitating in my AWC reservoir. I’m using Red Sea blue bucket and usually check the first couple batches of a new bucket after 24hrs mixing.

EDIT: AWC waster testing at 440ppm so that’s not it.

OP- sorry to clog up your thread I just thought maybe we could identify our common issue.

It is tricky, but calcium can actually be higher in the new salt water than in the tank and still a water change can reduce the amount of calcium IF the alkalinity in the new salt water is even higher.

For example,

If the tank is at

8 dKH and 420 ppm calcium

and the new salt water is at

12 dKH and 440 ppm calcium

then that water change will effectively reduce calcium when maintaining alk with a balanced alk/calcium method.

Imagine the corals using some alk and calcium in just the new salt water, back tot eh alk level of the main tank:

12 dKH --> 8 dKH
then calcium will drop
440 ppm --> 413 ppm

I don't know if this is likely in your scenario, but it shows the analysis of calcium alone is more complicated than just comparing values before and after

 

[Steve2020]

Can the RS Alk pro or Hanna Alk Checker be used to check RODI? I am not saying my RODI unit is not producing 0ppm Alk because my SW batch tank reads 8.9ppm and I would think it would be higher if Alk was in the RODI but I just checked the RODI water with 2 different test strips I use for the hot tub and it shows some Alk between 0-20ppm. I know these are not accurate to say the least. I have a 7 stage 200GPD HO BRS unit reading 0 TDS

 

[Randy Holmes-Farley]

Can the RS Alk pro or Hanna Alk Checker be used to check RODI? I am not saying my RODI unit is not producing 0ppm Alk because my SW batch tank reads 8.9ppm and I would think it would be higher if Alk was in the RODI but I just checked the RODI water with 2 different test strips I use for the hot tub and it shows some Alk between 0-20ppm. I know these are not accurate to say the least. I have a 7 stage 200GPD HO BRS unit reading 0 TDS

If a TDS meter reads 0 ppm TDS, there's no significant alkalinity in it.

Any normal titration kit can read RO/DI correctly, and it should change color on the first drop of added fluid.

I do not know if the Hanna can read it accurately, but it too should attain the endpoint rapidly.

 

[Steve2020]

Tested RODI and Hanna reads 0ppm. The Red Sea Pro did not change color on the first drop. It was clear. After adding a few more drops it turned a pale yellow, then added a few more and it turned a deeper yellow indicating a overdose of regent. Never turned blue or green. I am assuming this also indicates 0ppm.
I am still trying to figure out what is causing the drop in Calcium and not Alkalinity. If it is a testing error it sure is a consistent error over the past few months.
This is very interesting to say the least.

 

[Randy Holmes-Farley]

Tested RODI and Hanna reads 0ppm. The Red Sea Pro did not change color on the first drop. It was clear. After adding a few more drops it turned a pale yellow, then added a few more and it turned a deeper yellow indicating a overdose of regent. Never turned blue or green. I am assuming this also indicates 0ppm.
I am still trying to figure out what is causing the drop in Calcium and not Alkalinity. If it is a testing error it sure is a consistent error over the past few months.
This is very interesting to say the least.

how are you measuring calcium?

 

[Steve2020]

how are you measuring calcium?

I used to use the Hanna until I purchased the Red Sea Pro. A lot of people do not like the Hanna because of such a small sample size compared to the 5ml sample size of the RS so I switched. I have been using the Red Sea Pro for about 4mo now.

 

[Court_Appointed_Hypeman]

Production of nitrate from ammonia depletes alk. Consumption of nitrate (by ANY means) adds it back in exactly of the same amounts.

If nitrate is steady, no net change takes place, regardless of how much fast it is made and then consumed..

And if a change did take place (say, 20 to 10 ppm) then that is a single fixed amount of alk addition.

Thanks!

 

[Steve2020]

So, it is hard to remember everything that has been dosed in a 2yr period so I looked at my Profilux 4 dosing amounts over the past 2yrs and have come to the conclusion that it is testing errors. Below is the dosing amounts including corrections based on test's performed starting with today for the last 24mo:

Alk Dosed, Cal Dosed, Difference

Today: 0 0
3mo : 5870ml, 6244ml, 374ml more Cal dosed

6mo : 9788ml, 10821ml, 659ml more Cal dosed

12mo : 19215ml, 19625ml, 627ml more Alk dosed

24mo : 32522ml, 32339ml, 593ml more Alk dosed

Over a 24mo period there has been 183ml more Alk dosed than Cal probably due to fresh saltwater mixing at a slightly lower than my 9.0ppm Alk setpoint for my display tank.

Thanks Randy for all your explanations. That's what made me take a much closer look at what I thought was an issue.

 

[Lou Ekus]

OK so this begs the question, what are the proportionate calcium and alkalinity levels in the part C?

Tropic Marin defines partc as a sodium free salt mix. if it’s anything like their coral pro salt the alkalinity is not high.

@Lou Ekus any insight on what we are experiencing here?

I am in the same situation with products dosed and a bunch of fast growing SBS corals needing a higher amount of calcium.

The Balling Part C does not containe alkalinity or calcium. So it will not be a factor in this. @Randy Holmes-Farley is absolutely correct in saying that this is most probably one of two very common things. First is some kind of measurement error. @Steve2020 I am not saying that you are doing anything wrong exactly. Just that there may be some "introduced" error in the measuring process. This might be a methodology thing or a opporator thing or something else. But the actual measurement might be consitantly off by the same amount. Secondly, and this is the most probable, is that there is some alkalinity coming into the system in some other product. This could be a food or additive. This would make it look like you were consuming more alkalinity, when in fact, you were just getting extra from some place else and not adding enough calcium to m atch that consumption. Let me know what you find out after checking all your other additives.

 

[Steve2020]

The Balling Part C does not containe alkalinity or calcium. So it will not be a factor in this. @Randy Holmes-Farley is absolutely correct in saying that this is most probably one of two very common things. First is some kind of measurement error. @Steve2020 I am not saying that you are doing anything wrong exactly. Just that there may be some "introduced" error in the measuring process. This might be a methodology thing or a opporator thing or something else. But the actual measurement might be consitantly off by the same amount. Secondly, and this is the most probable, is that there is some alkalinity coming into the system in some other product. This could be a food or additive. This would make it look like you were consuming more alkalinity, when in fact, you were just getting extra from some place else and not adding enough calcium to m atch that consumption. Let me know what you find out after checking all your other additives.

Red Sea Colors ABCD does not add ALK or Cal to any measurable point and I was informed that the phyto I add is grown using Instant Ocean which I believe is higher in Alk than my salt mix but I only add 120ml every other day so that is not the issue. As mentioned in my last post, after looking at the Alk and Cal dosing history for the past 24mo off my Profilux 4, I would have to say it's looking more than likely testing errors which kind of sucks. I am very carful on the human side of things when it comes to testing so it must just be the inconsistencies in the test's themselves.