Would all you Oceanic salt user please test your magnesium levels

[golfish]

And post them

I've tested my tank and water change water levels using a 5 year old Salifert kit and a brand new kit, I getting around 1600 from both the tank and WC water using both kits.

I'm really thinking I have a bad batch of Oceanic salt.

[johnfr]

I recently totally replaced my crushed coral with Argamiite Sugar Sand. I emptied my tank, moved my lifestock to a spare tank and drained the main tank. The crushed coral was completely removed and the tank washed. I then put 150 lbs of well washed argamite in the tank and filled it with ~ 150 gallons of RO-DI water and mixed in the appropreate amount of Oceanic salt. It took 74 cups of the salt to achive SG = 1.023. Here are the parameters I measured after the salt mix had sat for 8 hours.

12/29/04
SG = 1.023
Cal = 580
Alk = 2.63
PH = 8.2
Mg was not tested.

I then let the tank sit overnite (12 hours) and retested before starting to transfer my fish & coral back into it.

12/30/04
SG = 1.023
Cal = 480
Alk = 2.75
Ph = 8.3
Mg = 1375

As you can see the calcium levels dropped signifficantly over night while the Alk went up slightly. I used Selfert for Cal & Alk,Coral Sea test for Ph, Reflectometer for SG and Seachem for Mg.

As I mixed the salt I noticed a white film start to form on the glass of my aquarium. By the time the water had cured for 24 hours this white film was getting quite heavy. It took me nearly 2 hours to scrap this from my glass with a great deal of effort and pressure. I totally trashed my Kent Pro scraper. Areas of this white film continue to build back up. It also is forming in my refuge. It is a real pain to remove.

I am thinking that the white film is calcium carbonate or argumite forming on the glass. I have wondered if it is some kind of reaction with the argumite gravel.

When I restarted the system I had about 130 gal of water in the refugium, sump and spare tank which had the old water. This all was mixed with the new water as the pumps began to cycle water through the system

I use saturated lime water as my makup. After two day of running The parameters were.

1/1/05
SG = 1.024
Cal = 420
Alk = 2.51
Ammonia = .05
Nitrate = 0
Ph = 8.3

After 1 week

1/8/05
SG= 1.024
Cal = 420
Alk = 2.63
Ammonia = 0
Nitrate = 0
PH = 8.2

Happily all the corals, clams and inverts are doing well with the exception of two Skunk Cleaner shrimp that succome to low O2 levels in the spare tank and got captured by the annemeys.

[Randy Holmes-Farley]

Oceanic runs high in calcium and magnesium. Check this thread:

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=407011

[johnfr]

Thanks Randy,

I have been following that thread and several other related to the high levels of Cal & Mg in Oceanic salt. I have certainly picked up on your poor opinion of the Oceanic mix. I am planning on moving away from it as soon as the current bucket runs out.

I would be curious as to what your thoughts are on this white film that I am getting is. It is on the glass, filters, pumps, overflows, everywhere. Is it Calcium Carbonate? Is it related to use with Argumite? What can I do to stop this?

[Randy Holmes-Farley]

You don't think it is any stirred up sand?

It may just be some precipitated CaCO3, although the sand should not cause that. The elevated calcium in Oceanic might, and the drop in calcium would support it, but the alkalinity would have to drop a lot (way more than 1 meq/L) to deplete calcium that much.

How fast are you adding the limewater?

Maybe the pH is really higher than you think, at least during limewater addition leading to excessive precipitation of CaCO3.

[johnfr]

I don't think it was the result of stirring of the sand.

The white film formed before any lime water was mixed in. In my system the limewater is dripped into the sump. I was not circulating any water into the main tank until after it was filled and aged for a day.

As I was filling the main tank (which took about 2.5 days with my 60 gal/day RO filter) I would add enough salt to equal the amount of water that had collected in the tank. So the first day when I had accumulated about 60 gallons of water, I added the first 25 cups of salt. (1/2 cup per gallon per Oceanic's instructions.) At the end of the second day I added another 25 cups and on the third day I added 24 which brought the salinity up to 1.023. I did this so that the majority of the water would be somewhat aged.

From the point that I started adding salt at the end of the first day, I had "Bathtub rings" of white material form. Before adding salt when I had pure RO water and the Argamite only, no rings were noticiable. These rings seem to be related to the region where the surface of the water was exposed to the air. I had a small power head circulating the water during the last 2 days of the fill process to help mix the salt.

I had also noticed this same phenominon a month previous when I converted my refugium to Argamiite sugar sand. The glass in the fug was coated white and the my pumps & heaters were all covered in white.

I will check the PH with another test to varify the PH.

Thanks for your comments.

johnfr

[Randy Holmes-Farley]

You mixed this water in the aquarium?

One often gets solid material that precipitates from salt mixes when water is added. These materials may include CaCO3 and a host of other things that may be added intentionally or as impurities in the salt mix.

[raydz]

I've been using Oceanic salt mix for about three months now....Magnesium was 1250 after mixing it up. Calcium was 425...so I was happy....

[Randy Holmes-Farley]

Magnesium was 1250 after mixing it up. Calcium was 425...so I was happy....


Dd you measure the salinity? It may be low to get those values.

[raydz]

Salinity was 1.025
Why do you say Salinity may be low?

[bierluvre]

Because due to readings e'one else has been getting it would seem that you didn't mix enough in comparison. ;)

[Randy Holmes-Farley]

If you raised that to NSW sg (1.0264), then the magnesium rises from 1250 to 1320. Not a big deal. But the fact that you get lower Ca++ and Mg++ than others would suggest that either you have lower salinity, or a different makeup to the solid salt that you started with (as bierluvre mentioned).

[raydz]

I have to admit... When I mix the salt I just add 1/2 cup per gal of RO water... Then a quick salinity check to make sure its close.

Could there be a diiference in batches of salt?

[Randy Holmes-Farley]

There could be batch to batch variations in ions and also in the moisture content, although I have no data on either for Oceanic.