Low Mag and Ca, can I do anything apart from dosing?

mr11 · Jan 27, 2016

So...

Ca 280
Mag 1050
Alk 9 dKH
Nitrate 0
Phos 0
pH 8.4 at the end of the day

I'm running GFO and Carbon and do a 8% or so WC about every 9 days with IO mixed to 1.025. I only have a couple coral, all soft but one galxea LPS. Why are my Cal and Mag so low? Definitely lower than what it should be with the IO. What can I do to correct this? I'm not keen on dosing. Thanks!

mr11 · Jan 28, 2016

Actually now that I think back to when I was first setting up the tank my LFS sold me some unmarked salt that probably didn't have the added elements like IO of RC. So if I want to bump it up is that something I do all at once or add to my top off water and do it gradually?

Sabellafella · Jan 28, 2016

but what are you using to measure ur salinity? The calcium is most likely a testing error and ur mag is low (edit look into what salt mix your using, for all you kno it could be something bad)

mr11 · Jan 28, 2016

I have a refractometer to measure salinity. Calibrated and temperature adjusting. I used Salifert for Ca and Mg testing, just curious why do you think it's a testing error? Because it's so low?

FlyinBryan · Jan 28, 2016

You won't hit numbers with water changes i tried.

Whatever you do..never put salt in your ato. Water evaporates salt doesn't. I just wanted to make that clear.

What kind of salt are you using? Id stick with reef crystals. I always come back to it.

I can't get around additives and if you have a high demand tank your levels will drop low in days, not weeks.

Your salinity is good. Keep your Mg elevated to around 1330-1350, that way you'll be able to keep alk and calc at higher levels.

If you need good and cost effective additives, check out brs. But don't try dosing through ato. All that stuff will precipitate out long before it gets in your tank, it will be no good. Getting a dosing system.

Plenty of videos out there. Invest more time in research and understanding the basic chemistry involved in all this.

Sabellafella · Jan 28, 2016

Yup and ur mag is low, depending on your salt mix if its regular IO your calc should atleast be around 340 and mag around 1200 at 35ppt , even if you have an explosion of corralline algae it would hault before your clc and mg reach that low. Off the top of my head only issues i can thing of is testing error or your sg is low. Do you do water changes often?

mr11 · Jan 28, 2016

FlyinBryan said:
You won't hit numbers with water changes i tried.

Whatever you do..never put salt in your ato. Water evaporates salt doesn't. I just wanted to make that clear.

What kind of salt are you using? Id stick with reef crystals. I always come back to it.

I can't get around additives and if you have a high demand tank your levels will drop low in days, not weeks.

Your salinity is good. Keep your Mg elevated to around 1330-1350, that way you'll be able to keep alk and calc at higher levels.

If you need good and cost effective additives, check out brs. But don't try dosing through ato. All that stuff will precipitate out long before it gets in your tank, it will be no good. Getting a dosing system.

Plenty of videos out there. Invest more time in research and understanding the basic chemistry involved in all this.

Appreciate it. I'm pretty convinced at this point my levels have always been deficient. I just got these test kits so I don't have a "before" reading unfortunately. I'm using regular IO, but I used some no name salt my LFS gave me when I set up my tank 4 months ago and didn't know what I was doing. I'm curious to see if my levels will maintain themselves if I ever get them up to par. I really shouldn't have any demand, just 1 small LPS and some snails.

Thanks for the recommendation and the tips. I definitely believe research is key, just wasn't quite sure where to start with this particular topic and everyone on here is great for guiding us newbies down the right path.

mr11 · Jan 28, 2016

Sabellafella said:
Yup and ur mag is low, depending on your salt mix if its regular IO your calc should atleast be around 340 and mag around 1200 at 35ppt , even if you have an explosion of corralline algae it would hault before your clc and mg reach that low. Off the top of my head only issues i can thing of is testing error or your sg is low. Do you do water changes often?

Thanks. I'll repeat the test tomorrow and see what I get. Test isn't expired at least. I do a water changes about every 9 days, maybe a little less often when I get lazy.

Randy Holmes-Farley · Jan 28, 2016

mr11 said:
I have a refractometer to measure salinity. Calibrated and temperature adjusting. I used Salifert for Ca and Mg testing, just curious why do you think it's a testing error? Because it's so low?

Yes, because magneisum is lower than consumption would cause except in a high demand tank left for a long time with no additions or water changes. In your case, the magnesium will exactly reflect what was in the salt mixes. Normal IO usually has way more than that, but I can't speak for an unknown material from an LFS.

Testing error is common with magnesium, although the Salifert kit usually seems OK.

Try the kits on some new IO salt water.

Downbeach · Jan 28, 2016

mr11 said:
I have a refractometer to measure salinity. Calibrated and temperature adjusting. I used Salifert for Ca and Mg testing, just curious why do you think it's a testing error? Because it's so low?

What are you using to calibrate the refractometer? If RO/DI or distilled water, you might want to get a proper 35ppt solution.

http://reefkeeping.com/issues/2006-12/rhf/index.php#13

mr11 · Jan 28, 2016

Randy Holmes-Farley said:
Yes, because magneisum is lower than consumption would cause except in a high demand tank left for a long time with no additions or water changes. In your case, the magnesium will exactly reflect what was in the salt mixes. Normal IO usually has way more than that, but I can't speak for an unknown material from an LFS.

Testing error is common with magnesium, although the Salifert kit usually seems OK.

Try the kits on some new IO salt water.

I'm mixing some SW now so I'll do that, great idea.

I did use 35ppt solution to calibrate the refractometer. Salinity is always what IO says it should be when mixing x amount of IO with x amount of water. Also double checked with a swing arm specific gravity thing.

Randy Holmes-Farley · Jan 28, 2016

mr11 said:
I'm mixing some SW now so I'll do that, great idea.

I did use 35ppt solution to calibrate the refractometer. Salinity is always what IO says it should be when mixing x amount of IO with x amount of water. Also double checked with a swing arm specific gravity thing.

OK, great. Let's see what the kits says.

mr11 · Jan 28, 2016

Results are in!

Fresh batch of SW mixed with IO.
Mag - 990
Ca - 300

Both within reasonable error of the results I got when testing my DT water. The question now is... bad test or bad salt? I find it unlikely that both tests are inaccurate. Unfortunately I have about a years supply of this salt on hand... Next step?

Randy Holmes-Farley · Jan 28, 2016

Maybe it is the salinity that is off. Both are off by about the same factor from what is normal in IO.

beaslbob · Jan 28, 2016

Same problem here with io in my tank and others people's tanks.

I highly recommend you do the randy diy two part.

In our case we used literally 3-5 pounds of Epsom salts to get magnewium from 700-800 to 1300 or so. but after that the diy 2 part worked like a charm. mag was never below 1200 or so again. calc and alk were easily maintained with inexpensive ingredients.

my ideas worth .02
Randy Holmes-Farley ideas worth a whole lot more.

mr11 · Jan 28, 2016

Randy Holmes-Farley said:
Maybe it is the salinity that is off. Both are off by about the same factor from what is normal in IO.

Just rechecked refractometer with calibration solution and retested salinity. Still 1.026

mr11 · Jan 28, 2016

beaslbob said:
Same problem here with io in my tank and others people's tanks.

I highly recommend you do the randy diy two part.

In our case we used literally 3-5 pounds of Epsom salts to get magnewium from 700-800 to 1300 or so. but after that the diy 2 part worked like a charm. mag was never below 1200 or so again. calc and alk were easily maintained with inexpensive ingredients.

my ideas worth .02
Randy Holmes-Farley ideas worth a whole lot more.

Glad to hear I'm not going crazy

. I'll look into that solution.

mr11 · Jan 28, 2016

Here's what I'm thinking of doing since I don't think my problem is from over consumption of elements. Short term solution is to bring levels up to 1350 Mg and 420 Ca using some commercial supplements like kent marine. Simultaneously I'll switch to Reef Crystals and just do WC's with the new salt as a long term solution. What do you think?

Randy Holmes-Farley · Jan 28, 2016

I agree that it is not likely from depletion, and raising seems OK if you confirm the results.

Just go slow, and I'd personally use something cheaper than Kent supplements, unless it is a small tank.

You might waits just one bit longer, to see the test results on some Reef Crystals and see if it is higher and not a test issue.

mr11 · Jan 28, 2016

Randy Holmes-Farley said:
I agree that it is not likely from depletion, and raising seems OK if you confirm the results.

Just go slow, and I'd personally use something cheaper than Kent supplements, unless it is a small tank.

You might waits just one bit longer, to see the test results on some Reef Crystals and see if it is higher and not a test issue.

Sounds like a plan to me. I'll pick up some Reef Crystals soon and rerun the tests to confirm. Then supplement from there if it looks to be a salt mix issue.