What can influence a tank's Mg reading - Page 2

Delphinus · #11 04-09-2009, 05:42 AM

Yeah, I got suckered again. I read post after post about how great a salt is and I think "I want to join this party! Please be my friend! I'm so lonely." It never works out. I kind of think a salt is just a salt. I dunno.

JDigital · #12 04-09-2009, 05:53 AM

I've been fighting to get my CA, Alk, and Mag up for that past 2 weeks.. Dosing every night any numbers just won't increase to the numbers I want... I don't have a packed SPS tank, so I don't know where all this could be going..

03/24/2009 Ca: 380-390 Alk: 6.4 Mag: 1155
03/25/2009 Ca: 370-380 Alk: 6.4 Mag: 1260
03/27/2009 Ca: 370-380 Alk : 6.4 Mag: 1110 NO3: Undectable
03/29/2009 Ca: 330-340 Alk: 7.4 Mag: 1230
04/01/2009 Ca: 380-390 Alk: 6.7 Mag: 1260

Delphinus · #13 04-09-2009, 06:21 AM

Could it be going out the skimmer? How's your skimmate production? The skimmer on this tank needs to be emptied everyday whereas my other 2 it's only once per week.

Sebae again · #14 04-09-2009, 06:43 AM

It could be going out the skimmer if you are not dosing to make up what you throw out. The big assumption with doing regular water changes is that water changes will make up for what is lost,so if you had a fish only tank it would work out as long as the fish never drank any water. The water changes only,with a good salt, make the new water on par with natural salt water. It you do only a ,10-20% water change it does nothing for the other 80-90% so every day our values become less and less. Unless we dose or do 100% water changes we will never win.

Delphinus · #15 04-09-2009, 06:48 AM

But I AM dosing right now, ie. not relying on water changes. I've gone through nearly a whole bottle of Mg so far this week and it's flatlined at 900. That's why I think it's odd? Why would the number not be going up at all. I'm using Tailored Aquatics Mg. 2 out of 3 tanks (with much heavier bioloads) are increasing, the one is not. Is there anything to watch out for that could be interfering with Mg or Mg testing?

Sebae again · #16 04-09-2009, 07:12 AM

Are calcium and alk up to par? Maybe take a cup of that tank water and see if you can get Mg up in that cup.

StirCrazy · #17 04-09-2009, 01:02 PM

ok, need some more info ont he tanks, what is in the ones that are good and what is in the one that is bad? (coral wise) also is there a sand bed in each tank and is it the same in each tank. are your Ca and alk the same in all 3 tanks? oh and is the low tank a new tank?

don't worry about the 24 hour mixing, as long as you are mixing it good it won't make a differance like that. and as long as it is mixed to the desolving poing it doesn't matter if it is 5 min or 5 days. once it is desolved it is desolved. I mix for 5 min with my drill propeller and then let the mag drive go for another hour. but after the 5 min with the propeller it is good.

I found DSB are good for sucking Mg out of the water. never had 1/2 the work to keep up Mg when I went bare bottom.

Steve

Delphinus · #18 04-09-2009, 03:03 PM

Ok sorry, I meant mix the salt itself, not the water with salt in it. I once complained about another premium salt brand that was reputed to have Mg at 1400, but when I tested Mg, it was 900. (I'm actually really starting to wonder if the problem is Elos can't tell me if Mg is <900 - it clamps at 900 - just on account I've never had a reading less than 900). Anyhow, I ranted about it, and one thing that came out of those conversations was that you're supposed to mix salt before you use it. For real. Isn't that the lamest thing? But I guess if they're adding this and that when they're making the salt up, the proportions may be all correct as far as the total batch is concerned but the dispersal may not be as homogenous as one would like.

Tank with the flatlined Mg is not new and has no sand. It has maybe a half dozen 1" SPS frags, two smaller colonies, a bubble coral, a gigantea carpet and two ocellaris. Maybe about 3 billion aiptasia though. It's a 24x24x12 shallow lagoonal thing.

Ca is 360, Alk is 7 and Mg is 900.

The other tanks have similar but different readings. One has Ca 420, Alk 7 and Mg 1100 (as of last night anyhow, I am still raising it though), the other has Ca 370, Alk 7, and Mg 1050 (also still being raised). One other is a BB tank, and the last one has a 1" skiff of sand.

I am betting dollars to donuts now that the issue is in fact the test kit can't tell me a number less than 900. I will test tonight with Salifert and see what shakes out.

StirCrazy · #19 04-09-2009, 11:35 PM

Quote:

Originally Posted by Delphinus

I am betting dollars to donuts now that the issue is in fact the test kit can't tell me a number less than 900. I will test tonight with Salifert and see what shakes out.

If the salinity levels are the same I am with you on the test kit.

no reason for excessive Mg consumption in your tanks.

Steve

Delphinus · #20 04-10-2009, 05:42 AM

Salifert says 1005, Elos still says 900 tonight.

I was wrong about Salifert resolution at 30, it's 30 units apart on the lookup sheet but going up in 0.02ml increments. So it's really 15.

I also dropped the vial for the Elos test kit and shattered it into about a billion little shards. Yay me. Man those things break super easy.