Magnesium

[WaterDogs]

Boomer,

Could you explain this "units" and "real SG" to us?

1.024 -15 units = a real SG of 1.024 - .0015 = 1.0225 = 30 ppt

You are way to low on your salinity and need to get to 35 ppt. Your refract needs to read;

1.028, which with the error correction = 1.028 - .0015 = 1.0265 corrected = 35ppt NSW. Raising your salinity up to NSW will give you a 15 % increase in Mg but that Ca will also increase 15 %. Of course that would be if you were starting with all new water. I like so far WD suggestion and see what you get

 

[CarlaW]

WD,
20 gallon water change and lots of seachem ( ),and end result, Mg=1275. I think I should be able to maintain that level with water changes, don't you?
Thanx for your help.

 

[Boomer]

WD

All refracts that you buy are calibrated to an NaCl solution. 35 ppt of NaCl is no the same thing as 35 ppt NSW. NSW has a higher refraction of light than NaCl. That off sets the refract by "15 units". I say 15 for this reason. A refract may be giving the "salinity in ppt, % solution or SG, so

Refract reading = 35 ppt - "15 units" 35 -1.5 = 33.5 ppt NSW

Refract reading = 3.5 % solution - "15 units" = 3.5 % solution - .15 =3.35 % NSW = 33.5 ppt NSW

Refract reading = 1.0265 SG - "15 " units = 1.0265 - .0015 = 1.025 = 33.5 ppt NSW

If you want to DIVE into it here is something for you to read I helped Randy collect data for;

Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm


That is mostly what I have read/heard; when I was using Oceanic salt at 1.026 on a refract my Mg was always close to or over 1500

OK, because we know there have been many getting very high Ca almost to 500 mg / l.



Charlie

You seem to be on track

 

[CarlaW]

Boomer, could you address raising the salinity in an existing tank? Thanx for your guys help. I don't normally like to cahnge things that quick in my tanks, but I don't see anything bad goin on, so I guess I'm alright.

 

[WaterDogs]

I'm glad your problem is solved Charlie and thanks Boomer for clarifying!

Dwaine

 

[CarlaW]

WD, ain't nothin solved yet, just cured for the moment. We'll see what happens here with the next few weeks.

 

[WaterDogs]

WD, ain't nothin solved yet, just cured for the moment. We'll see what happens here with the next few weeks.

If you are dead set on only changing 20 gallons a week of water that is fine but the Mg level will go down so just adjust with an additive.

To raise SG on my 75g I take out a gallon or two off water and add the 1/2 to 1 cup salt mix and add back to the tank this will raise it I think 1 point.

Dwaine

 

[CarlaW]

I was lookin at maybe changing 30, but I still think I might have to supplement. I should buy stock in the company that makes epsom salts. I like the idea about raising salinity tho, thanx.
I need to keep an eye on the Mg this week to see just what the consumption is and will be. I'll try to keep this updated!!

 

[fishermann]

Charlie You can go to the drug store and get some epson salts and bring your mag up easy, just do it slowly. Mix like 2 cups with a gallon of water and check your mag level after a while with a Salifert kit. This well bring it up very easly without big water changes and then you can use the mag spplements to keep it at the proper level, but using Oceanic salt, which is what I use, You tend to have a high mag level. I was using Kent when I had the low mag problem with a level of 1090 and I brought mine up to 1350 in 4 or 5 days with epson salts which Mojo told me about since he had had the same problem. You want your parims all to be around nsw and that is 1290 for mag.

 

[Boomer]

could you address raising the salinity in an existing tank?

No more than 1 actual unit / week, so it would take you 4 weeks. You are /were at 1.024 and need to get to 1.028. ie., 1.024-->1.025-->1.026--->1.027--->1.028.

This will make it easier

http://www.saltyzoo.com/SaltyCalcs/SalinityAdjust.php

Make sure you use the same units, as in ppt or SG

EDIT

Don't use Sg ONLY ppt in the window. You get funny answers with SG. So, at 30 ppt and you what to go to 35 ppt @ 50 gal / week WC

 

[CarlaW]

Boomer, if I am following that correctly, that would mean that I wouldn't actually be doing a water change, I would just be increasing the salinity of the water I removed from the tank, and then replacing the water into the tank. Please correct me if I am wrong.

 

[mojoreef]

Charlie you could do it via a more concentrated sg with the water you are adding via the wc. So you could make the WC water as concentrated as required to raise the sg a point a week.
I would not put so much worry into the Mag level being low, with that salt mix its going to be a to high problem really quick anyway.


Mike

 

[CarlaW]

Ok, thanx mojo for helping out. Your solution is kinda what I was hoping. The calculator that Boomer gave me set the parameters for me. I was just a little confused, I'm old, give me a break.
Again, thanx all you guys for your help, it is much appreciated .

 

[fishermann]

I emailed oceanic a six or so weeks ago asking them about these reported high Mag readings people have been having with their salt. I have not had an issue using it and infact I like the salt and have been using it for about 6 mos. now and like the sps growth I'm getting since switching and it has been alot easier to keep my parims right. I run my sg at 1.025 with a refractometer and my mag levels stay dead on 1290. Anyway their answer the next day was that their product is made to have proper mag levels at a SG of 1.025 and that running the SG higher well raise the mag levels. I raised my SG to 10.26 in my softie tank and took a test one week later and the mag levels had went up to 1350 and then the next week to 1390. I since lowered it back down to 1.025 and things are almost back to normal. So I believe that they are correct and that you need to keep your SG at 1.024-1.025. Charlie you were at 1.024 which with a mag level of 1250 would be about right according to them. I have no mag issues with the salt at 1.025. Thanks

 

[cwcross]

Edited...for a mistake...C

 

[mojoreef]

John if charlie was measuring at 1.024 using a refractometer his salinity after compensation would be 1.023 (little less actually) This woould mean that his salinity was 14% lower then NSW at 35ppt or 1.027. Thus all the elements that make up the water would also be 14% lower if they were in balance. So at the salinity of 1.023 his mag level should be 1109 (1290 - 14%). If his mag level right now is 1275 then it is around 13% higher then it should be, so 1275 -1109= 165 parts to much, if the salinity remains consistant that means a 165 parts of something else needs to come out of solution, then add the cal being to high and its even more, alk is definately one of the elements that is being effected.


Mike

 

[mojoreef]

Sorry Collin I posted at the same time


MIke

 

[cwcross]

No problems mike. I accidentally failed to read the entire thread and based a response only after reading the first page... Here is my response...however, it apprears that a useful adjustment was discovered for the tank...however, I will post my reply to take with a grain of salt...Collin

Previous edited post:

1250 for Mg may be an ideal target. However, I suggest that the difference between 1200 and 1250 ppm of Mg may be well within the error of the test kit. Reef kit titrations are notoriously inaccurate and there are fundamental reasons why this is true.

Think of it this way. 50/1250=0.04 or 4%. This means you are only 4% away from your target. This is a minor difference. You might consider waiting until you are more like 10-15% away from your target (or maybe even 20-25). When dealing with target levels in the aquarium, these are not usually critical values. Just targets to keep your eye on over time. If things start to get way out of whack, or you are actually having problems, I would suggest action. I don't suggest trying to keep levels pegged at thier optimums all the time though. Just some thoughts...Sincerely...Collin

 

[Boomer]

Charlie

as Mojo said Charlie you could do it via a more concentrated sg with the water you are adding via the wc. So you could make the WC water as concentrated as required to raise the sg a point a week

The calculator does this for you. You could raise the salinity 1 point / wk with 1 gal of water. Yes you could remove tank water and increase its SG, IMHO I would use new water.

In the cal window type in

475 gals = (net water)
30 ppt = what you have
35 ptt = where you want to go
1 ppt= change / week
1 gal= size of gal WC. or 5 gal., 10 gal etc.


For a 1 gal change = 1.46 sg / 505 ppt

for a 10 gal change = 1.059 sg / 77.5 ppt

for 50 qal = 1.03 sg / 39.5 ppt

 

[DonW]

What would the draw back be to just adding salt to your evap top off?
Not to steal the thread, but what is the formula used by calculators for ca/alk balance?

Don