Elemental balance

[Schnizzle]

My question for the experts is this, can the lack of trace elements have stalled consumption of Ca and Mg in my reef?

I’ve been fighting with high Ca and Mg (as high as 530/1680) for a year and I finally got it down.

Prior to current events I switched from Reef Crystals to regular purple box IO salt around eight months ago trying to lower this.
Another side note, I mainly started dosing for lack of iron because my macro algae had stopped growing.

Six weeks ago I started dosing trace elements (Tropic Marin K+ and A-) that I was zeroed out on and my consumption sky rocketed! To the point that I’m finally down to reasonable numbers. Tonight’s results post yesterday’s water change. I'm actually concerned that my alk is going to go too low. haha

I also have ATI elements Iron, Vanadium, Molybdenum, Manganese, Nickel and Iron that I dose individually.

1.0260 d SG
7 dKH
1380 Mg
420 Ca
12 NO3
0.08 PO4
8.2 PH

I’ve noticed good growth and bright colors in the reef the past few weeks. This includes some monti's that I had not seen any sign of stony growth on until now. I’m not sure who is happier, them or me.

Feel free to interrogate me, I'm sure there is a lot of additional information needed.

 

[Randy Holmes-Farley]

Certainly growth of corals and all photosynthetic organisms (including algae) may be limited by one or more trace elements if they are sufficiently low.

That said, there is zero chance the organisms in your tank dropped magnesium by 300 ppm in 6 weeks. It wouldn't drop by more than about 1/10th of the amount calcium declined, assuming no dosing of either. That drop is due to other reasons, maybe test error, maybe salinity changes, maybe water changes (if you did any).

 

[Schnizzle]

That makes sense.

I do a ~20% (~23 gallons in a 113 gallon system) water change every week or two. I buy salt in bulk so I'm still working the same run I have been for months. Probably two changes left before I move to the next batch.

No dosing other than what I described above, starting six weeks ago. Salinity has been 1.0264 to 1.0266 with the exception of spiking to 1.0270 on 8 November. I have a refractometer that I use 35ppt solution to calibrate before every use.

27 March, 8 November and 17 June numbers are from an ICP test. 20 April numbers are my testing and I sent off another ICP test at the same time to verify. I purchased another Ca and Mg kit after reading many threads where people had high Mg and seeing that the reliability was suspect. Both tests are typically within a max of 20 points of each other. I didn't see any of those threads come to a conclusion with an explanation.