Rising Mag

Tested my new batch of WCWater. I mixed it Saturday and tested it today. I use Instant Ocean.

I mix to 1.028. I do that because I maintain my SG at 1.027 and by the time I do a water change it measures 1.026. So, it brings it back to 1.027.

Also, I use dechlorinated tap. I have run the same tests on that water (using freshwater tests where needed) and it always measures out 0. I do have plans to add an RO/DI unit but I have to make some modifications to my wet bar first...

Ca: 500
dKH: 20
Mg: 1520
PH: 8.2 (maybe 8.3 - hard to tell on API test)

And it was 70 degrees.

I found these results very interesting.

I will test my tank water Friday or Saturday and compare it to the tests before the WC (11/30 tests, 12/5 WC, 12/13 more tests) and then that can be compared to what my WCWater test results.

Hope that's helpful to you DrFrag. It will be to me!

 

Your tap water has magnesium in it, good that it brought your calcium up (or have you been dosing anything?). Leave the tank alone, no more water change for a few weeks, and see if those levels in your tank go down, Then just mathematically find out how often you can use your tap water to dose your tank for magnesium, until RO/DI - to maintain the levels you want. Unless it was because you didn't mix the salt up correctly, that must be the source. Here is an article on how Instant Ocean salt mixes in water with "ideal" characteristics:

http://aquariumwatertesting.com/AWT_Salt_Analysis_0208.pdf

 

Thanks for your time and effort, also thanks for your input here, you will get some karma for that!8) BUT, there are a few more questions I have for you.... Does the bucket have a batch number on it? What did you use to measure specific gravity? Did you adjust to the temp of the water?
Also RO water would have been nice but beggers can't be chosers!!;D
Thanks again!

Anyone else use RC and RO/DI water? PM please as to not threadjack!!

 

Thanks John. I will read that.

The measurements

Ca: 500
dKH: 20
Mg: 1520
PH: 8.2 (maybe 8.3 - hard to tell on API test)

are of my fresh batch, before it is added to tank. The numbers are high, but once it's in the tank and diluted I expect the numbers to go down. I will measure again this weekend and see if these values in my tank did go up (I expect they will).

Other than WC, I've never dosed anything. EDIT: And not counting my tap top off water

I tested my tap for Mg and it changes colors on the very first drop... which I wasn't expecting. I figured my tap would have Mg in it too... doesn't appear to be so. I should note though, the test I had for this is generic and just says "magnesium water test" or something similar. It doesn't say marine, so I assumed it was good for fresh...

But I agree, the rising mag must be coming from my tap - there's no other explanation I can think of and it is likely that Mg test is for marine (I assume you can't use same test on fresh and salt). (My marine test is Red Sea).

But I can't not do top offs.... so for now, I'm stuck with tap on that. I will probably do the work on my wet bar after the holidays. I'm trying to figure out how I'm going to store the water in this area (things have to look clean and neat at my house).

This is also a reason I haven't added coral yet.

Bucket. The salt mix? It's a bag. I will check tonight and post a batch number.

I use this to test (hijacked pic)



I did not adjust for temp as I don't know how. As long as I'm consistent . . .

This topic has got my interest and my rising mag question is answered enough. Please do hijack this thread at this point as I want to follow this too!

 

I have to go to work peredhil, but I will interject more then.... When using a swing arm hydrometer, the SG is only accurate if YOUR water is 78degrees, anything away from that, you need to adjust the SG. Google, temperature, salinity chart or something, there is a link that will show at what temps your TRUE salinity/SG is, otherwise I will find it and post it when I get home.... I am late already so until then....

Happy reefing!

 

Mg does serve one critical factor in a reef tank. Mg increases the concetration of free calcium ions because Mg ions will bind with carbonate ions first. Because the calcium is not bound to carbonate it is free for use by corals. Additionally, the magnesium carbonate only weakly bonded and so the carbonate can still perform its main buffering role.

 

Please ignore the poor spelling and grammar of the last post.

 

It is very important that both temp and SG is correct when taking these reading. With your water only at 70 I would suspect your SG is off and therefore all other readings are not accurate

J

 

Good advice. One way around this problem is to get a refractometer. The automatically correct for temperature. They are also way quicker and less messy (no flicking bubbles). I got one online for $60. Oh yeah, they are way more accurate too.

 

http://www.deltaenvironmental.com.au/management/Lab_methods/hydrometer_correction.xls

There is a temp correction for hydrometer.


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