Reef Discussion

[potatocouch]

The funny bits about my tank is that I always playing catch up with Magnesium.

On Sunday, I brought it to my target Magnesium @ 1,320 ppm and by today (Tuesday), it is down to 1,260 ppm.

For a 2 footer CADE cube with 1x huge frogspawns, 2x small hammers, 1x small torch, few mushies, rics, zoos, leather ... the daily consumption of Magnesium is 30 ppm (Salifert test - long expiry).

The amount of increase acceptable for Magnesium as per Red Sea recommendation is 10 ppm.

Which means, on daily basis, I would need to dose 3 x 10 ppm.

Don't you think something is wrong here?

 

[Mattres]

What's you Alk and Cal?
I think you'll find the tank isn't consuming that much, the magnesium is just changing in regards to your Alk and Cal.
I forget the chemistry intricacies but if you have the parameters out of whack it could be causing it.

http://reefkeeping.com/issues/2006-06/rhf/

 

[potatocouch]

What's you Alk and Cal?

@Mattres

Alk was raised to 9.3 (measured on Sunday morning) and as of this morning (Tuesday), it dropped to 8.3.

Ca was raised to 430 (measured on Sunday morning) and as of this morning (Tuesday), it dropped to 410.

All measurement was taken with Salifert.

 

[Mattres]

Those numbers as they stand at the moment are pretty good, I'd try to stabilize the tank at that. Magnesium at 1260, is fine and close enough to 1300 with our test kit accuracy anyway.

 

[Savage Henry]

When you say you brought the level to your target, are you re-measuring just after you added reagents? Perhaps you are not allowing the tank to settle long enough before you are re-measuring?

Maybe measure once a week on the same day and do your additions on the same day each week to allow for consistency?

 

[potatocouch]

When you say you brought the level to your target, are you re-measuring just after you added reagents? Perhaps you are not allowing the tank to settle long enough before you are re-measuring?

Maybe measure once a week on the same day and do your additions on the same day each week to allow for consistency?

@Savage Henry they're not tested straight after dosing. From memory, I give it approximately good 5 - 6 hours (overnight) for a good mix in the tank and do the test early morning. So logically speaking, when I test early morning, this should have been done on a well truly mixed water.

From my calculation this morning, it seems that my daily usage is:

• 30 ppm of Mg
• 0.5 dKH of Alk
• 10 ppm of Ca

Hence, what am planning to dose on daily basis is:

• 55 ml of Reef Foundation C
• 10 ml of Reef Foundation B
• 10 ml of Reef Foundation A

And do another retest on Saturday morning (before WC).

If the number out of whack, then the consumption calculation is incorrect.