Magnesium

[fishermann]

Mike You guys are giving me a headache LOL , but can't you run the sg at a lower level like Oceanic says, that is what i'm doing and my parims are pretty normal and the corals are growing good and look great with this salt.

 

[DisturbedReefer]

I'm using a pinpoint salinity monitor, does this have to be corrected like the refractor or is it correct?

 

[cwcross]

Collin, I have figured it out. Mikey does not have live corals in his tank he has those dead bleached ones, so now you can see why he is concerned and thus would be correct in that regard Those dead corals would produce an awful lot of fresh carbonate surface areas, that would lower the Ca, Mg and ALk

How about those plastic ones you can buy? I thought I saw pictures of those in his tank too!

In fact, I think plastic corals are the way to go. Then I won't even have to worry about my paramenters.

regards...Collin

 

[cwcross]

Ok I will stay out of the orange world. lol

So serious question. Wouldnt the levels of 1500 and 500 make the whole balancing act problematic?? If a person wanted to run their parameters at NSW levels , say at 415 cal, 1290 magnesium and 7-8 dkh what do you do with this salt to make it work??

MIke

Well, I don't think it is really that critical. Test kits aren't very accurate anyway. Mg of 1290 or 1500...no difference really. Alk 7-8..same diff. Same with them all. I haven't even checked my ca or alk in 2 months. I just throw some Kalk in there now and then. I know approximately what my demand is so I throw it in near that rate. Maybe I am too loose and I plan on checking this week. However, my corals are growing just fine. In fact I have an open brain (sympafelia sp?) that is a beautiful pink green. It was in terrible shape when I got it. I put it in my tank about 3 months ago. It languished for a while and is now re-growing tissue to cover the exposed skeleton. Making a nice comback. But I thought I might lose it after all at first. I got it dirt cheap.

I'm not suggesting people neglect their tanks. Just suggesting that being pinpoint accurate is not really necessary.

However, if one wanted to use the salt on the table, what to do is to mix it to whatever specific gravity led to Ca and Alk and Mg levels you want. Then add pure NaCl to raise the salinity to whereever you want it. Same with any parameters. This can be generalized to say that one could mix the salt until the first parameter maxed out to the desired level. At this point all the other parameters would be low. Then each one that was too low could be raised until it came into balance by using pure chemicals. Once everything was balanced...if salinity was still to low...make it up with NaCl. Just seems like a lot of work. There are salts out there that have the proper balance. However, we won't get into that.

I feel guilty now. I need to run home and run some reef tests...Collin

 

[cwcross]

I'm using a pinpoint salinity monitor, does this have to be corrected like the refractor or is it correct?

Don't know what a pinpoint is. I'll defer to boomer or someone else here...sorry...Collin

 

[NaH2O]

Collin, I believe it is a conductivity probe (?). It measures in mS, and I believe it comes with a calibration solution to 53 mS, but I'm not sure what that solution is. Did I confuse you more?

 

[fishermann]

Collin without getting into a big debate on salts and such, If it doesn't bother you what salt do you use?

 

[cwcross]

Collin, I believe it is a conductivity probe (?). It measures in mS, and I believe it comes with a calibration solution to 53 mS, but I'm not sure what that solution is. Did I confuse you more?

Well, this won't be perfectly accurate either then. Conductivity is based upon concentration of ions.

If we consider a set of different pure salts at equi-molar concentrations and compare them, then each salt will have a slightly different conductivity due to differing ionic mobilities. For instance, potassium iodide (KI) will have less conductivity than potassium Chloride (KCl) at the same molar concentration. This is basically because a large ion (I-) travels more slowly through water than a small ion (Cl-) due to its larger hydrodynamic radius and associated viscous drag.

The moral of this is unless you calibrate on a solution with the same ratio and groups of salts, then you will not be perfectly calibrated in seawater.

Also, concentration is dependent on temperature. Concentration has units of mass/volume. When temperature changes...volume changes and so concentration also changes. Thus the instrument should be adjusted for temperature.

How large are these effects? I don't know exactly. I would guess the conductivity effect is quite small if the calibrant solution is designed for sea water. Temperature effects will be small fairly small to but might be a little larger.

However, in the vain of my last post on this thread. I wouldn't worry about it. Maybe Boomer has some specific details to give an adjustment factor. However, animals are much more sensitive to changes in salinity etc. than to the specific salinity. As long as you keep your salinity stable and near the ideal range, I wouldn't worry.

Sincerely...Collin

 

[cwcross]

Collin without getting into a big debate on salts and such, If it doesn't bother you what salt do you use?

I PM'd you...C

 

[mojoreef]

LOL Collin what salt do you use????? No big deal saying it here my friend, just as long as you know who stays hidden

Ok in a chemistry world I can see where mag being high might not have an impact but it does in a biological world. Also from a chemistry stand point if you have a calcium rate at or over 500, that is going to make alkalinity tough to raise up know? especially with magnesium on its side. Then if you take that to the biological side of the game with corals it can become a big problem with calcification??


Mike

 

[cwcross]

Ok in a chemistry world I can see where mag being high might not have an impact but it does in a biological world. Also from a chemistry stand point if you have a calcium rate at or over 500, that is going to make alkalinity tough to raise up know? especially with magnesium on its side. Then if you take that to the biological side of the game with corals it can become a big problem with calcification??


Mike

Understood Mike,

I do not mean it does not have an impact. I just mean it is not critical in some cases. Corals will grow over a wide range of most parameters. They may grow best at some cerain set of parameters. They may grow worse at others (or even have negative growth). I just don't see it as critical to try and maintain values too precisely. Certainly if things get too far out of whack, it is never good. Some animals are certainly more sensitive to differences in one thing than another, while another may not care at all about that one but be very sensitive to something else. Even in the ocean, mineral species both fluctuate and also vary widely from place to place. What is typically quoted are "average values"...like 35 ppt salinity.

Things certainly need to be kept in specific ranges and each individual species of mineral has interdependencies with many others, such as Mag and Ca solubilities. However, allowing things to vary slowly over reasonable ranges, when considering the whole picture, just doesn't seem to have a large impact on my tank.

Just my opinion though...Collin

 

[mojoreef]

I hear ya Collin, I also dont think folks need to be so critical. I must admit I did think mag had a chemical impact on alk, my bad. One thing I dont like to see in reef tanks is high levels of calcium, it makes the coral work so hard to grow and when thier is a deficiency of carbonate the problem tends to magnify. Corals are definately able to acclimate to alot of conditions for sure, its just tapping that energy budget tends to keep them riding the line.

I still dont know how to deal with the levated levels of mag and calcium. I can leave the mag to a point but calcium at 500 and a low alk is really unacceptable for a tank full of hard corals. I have been telling folks to just switch salt brands to avoid it, it that your basic answer to???


Mike

 

[Boomer]

Collin

The std chemical oceanographic method for measuring salinity is Conductivity. It is based on the std state of equation, found in any seawater manual or chemical oceanography text.


The std equation of state for seawater is

K15 = Conductivity of seawater sample / conductivity of std KCl solution @ 15 C 1 ATM and
the KCl being at 32.4356gkg

S = 0.0080 - .1692 K15 exp 1/2 + 25.3851 K15 + 14.0941 K15 exp 3/2 - 7.0261 K15 ² + 2.7081
K15 exp 5/2

If the conductivity of the sample is 53, 225 uM and it is the same for the KCL, then K15
=1. If you plug that 1 into the equation it = 35 ppt



This is what those 53mS solutions are, std calibrations solutions for salinity via conductivity. You can go to website after website and see oceanic salinity tracks via conductivity. Dr. Frank Millero, an old friend of mine, is a one of the pioneers in this filed. He also is author of;

Chemical Oceanography

Collin's reading assignmet, he is not special :lol::lol:

Unesco (1981b) The practical salinity scale 1978 and the international
equation of state of seawater 1980. Technical Papers in Marine
Science 38, Unesco/ICES/SCOR/IAPSO.

http://www.umass.edu/tei/mwwp/acrobat/sm2520salinity.PDF

http://www.es.flinders.edu.au/~mattom/IntroOc/notes/lecture03.html

Calculator;( don't anyone confuse density with SG, not the same)
http://fermi.jhuapl.edu/denscalc.html


Randy also did this long ago and has some of your concerns in it.

http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=1804&cid=124&search=

 

[DisturbedReefer]

So if the calibration standard is 53mS and this is what I am calibrating with, do I still need to make a compensation for NSW as you would for the refractor? Here is a shot of the scale that comes with the pinpoint unit. I just want to make sure that I'm getting the salinaty part right since I'm one of the unfortunate ones that is using Oceanic as well...I have a full bucket of IO ready to go for my newest tank project

 

[cwcross]

I still dont know how to deal with the levated levels of mag and calcium. I can leave the mag to a point but calcium at 500 and a low alk is really unacceptable for a tank full of hard corals. I have been telling folks to just switch salt brands to avoid it, it that your basic answer to???


Mike

That is the easiest thing in my opinion. The only other option is to buy reagent grade NaCl to supplement salt. The only reason that they don't want to change formulation is a cost and profit issue. Their cost will be higher if they add another 0.8 lbs of NaCl / hundred gallons mixed water. Easy to fix...just costs more. They would rather sell a more profitable salt and let the corals eat the difference. However, the other option is just to run salinity at 1.023 or so. I doubt this really has much impact.

Collin

 

[cwcross]

So if the calibration standard is 53mS and this is what I am calibrating with, do I still need to make a compensation for NSW as you would for the refractor? Here is a shot of the scale that comes with the pinpoint unit. I just want to make sure that I'm getting the salinaty part right since I'm one of the unfortunate ones that is using Oceanic as well...I have a full bucket of IO ready to go for my newest tank project

After reading some of boomers homework assignment...I would say no. You are OK with the standard calibrant for all intents and purposes...Collin

 

[DisturbedReefer]

Yeah, that's what I was getting out of it as well, just wanted to make sure I wasn't missing something there...Boomer?

 

[Boomer]

Just to back up Colin, no corrections are needed, UNLESS your meter does not have temp compensation and I pretty sure it does.

 

[Electrokate]

Just to throw a little monkey wrench into our expected outcomes...
I had a problem with a reputable brand of salt which sent my tanks into a tailspin from hell. Tried to correct with water changes, got worse, finally made up new water, circulated and heated for a day and then tested it at 1.025 (per plastic cheapo meter)... Got 620 ppm for the Ca and dKh 6, ph 8. Emailed the company, they said my test kits are bad. Got 3 more brands to test alk and they all said the same low result. For the Ca bought a Hagen kit, got 760 Ca. Found a different batch of Hagen Ca and tried that, got 740 ppm. Gee, should have stuck with the results from TropicMarin's kit! "Only" 620 which the salt manufacturer agreed was way too high! I didn't email the salt manufacturer again as since found others have had the same result from this brand-random bad buckets. When they claimed to have found them on lists such as this everyone poo poohed it, impossible, the manufacturer has a stellar reputation! So am not going to name them here. Besides, that batch is sold and gone, and any manufacturer could be next.
Anyways, my ph crashed but since I am a test nazi I caught it before too much damage was done. A friend using the same batch of salt was not so lucky, he lost every living thing in his tank. All he noticed was low ph as he uses 5 in 1 test strips and nothing else, and doesn't know how to even really read that test.

Previously I had taken a whole bunch of brands of aquarium test kits and run them side by side. Found some were really entirely useless right off the shelf, others fairly consistent but all slightly different. The tests I am now using are by salifert for alk, Aquarium Pharmaceuticals for nitrate and all others by Hagen. Some of the other brands really stunk... amazing. One you couldn't even get any liquid out, the precipitate had solidified completely at the top of the bottle, not sure how that happened... It was brand new off the shelf from a major box store. Have stuck with the brands that are cheap and likely to be used by my friends and customers. Don't think customers are going to be happy if I try and sell them the really expensive kits so want to find the best of the cheapos. As I work in the industry, don't think I should mention names of the real stinkers. We still sell salt by the company that sent the bad batch, gee it was really cheap that time too, think they knew. We don't sell the test kits by the company that failed my kitchen table comparison though, and the salt manufacturer has been good since, not that I will use them again.

Moral of the story, even the best and most reputable manufacturers are putting out unreliable batches now and then, and the test kits are not all that accurate either.
Also was using a reputable brand of 2 part additive and both bottles had significant precipitate in the bottom. I have no idea how much of the chemistry made it out of that bottle and in what proportions, which sucks.
Think I will keep doing my little chemistry experiments...
I have part of an art degree and that is my higher education. Should have stuck with my original interest-non mammal vet med. Art school was pretty light on the whole chemistry aspect of our education. All I know is what you guys teach me so thanks for doing so!
Kate

 

[cwcross]

Well Kate,

looks like you have common sense enough to make up for your lack of chemical knowlege. Interesting info and evidently a good catch on your part.

You elaborate on a point I was trying to make a while back. When comparing results of different people using different test kits in different environments...results can differ significantly.

One persons Ca of 380 is anothers persons 450.

Observational skills, being consistent, keeping logs and sticking with what works are very important in this hobby...

regards...Collin