Trouble Raising Magnesium and Calcium

[ekean45]

Over the past several months, I have been trying to raise magnesium and calcium levels with supplements and it does not seem to be doing very much.

65 gallon reef with a 10 gallon refugium (just added fuge a few weeks ago). I dose vodka - been doing that for about 3 years - tank has been running a bit over 4 years.

I had been using filtered tap water until about end of January this year. Since beginning of February, I have been only using RODI - did quite a few 30-40% water changes for first few weeks and now do 10% changes religiously every 4-5 days. Coral looks better than ever and fish look great. Have an HOB Octopus skimmer.

Nitrite, nitrate, ammonia and phosphate are 0.

Any suggestions? Since coral seems to look good and appears to be growing / splitting, do I need to worry about the Mag/Calc levels?

Here is a chart of the log of the metrics.

 

[Gregcoyote]

Traditional wisdom would warn you that the calcium and Mg levels are too low. Alk looks about right. I mix my own supplements and I can tell you it takes a surprising amount of Mg to raise levels to "normal." Same with calcium. They balance each other and low levels effects some corals and others don't seem to care. My caps would all suffer if I got the values as low as yours. Look at the BSR videos on the topic. They are excellent and show you the best and cheapest way forwards.


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[Mr tap water]

Hi there
Here's a couple of suggestions you could try raise your Sg Up to 1.026 this will help elevate levels. Secondly when you first buy your salt do you give it a good mix up as sometimes some of the major elements can sometimes sit at the bottom. thirdly it can sometimes depends on what brand of salt you use some have higher mag and calcium levels then others it might be worth having a look at other brands i'll Salt with higher levels.
If none of the above works you're only real other solution is to dose manually with some concentrated magnesium, and same goes for the calcium sometimes calcium levels can drop quicker and usually to do with how many Stony corals you have. I hope you get it sorted soon good luck. [emoji846]


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[ekean45]

I'll watch the video's - thanks for the advice

I do mix the salt. I make my own RODI and have a mixing station. I'll look into raising the salt first since that should be a fairly easy fix.

 

[Gregcoyote]

If you have a lot of stoney corals, you will need a lot of water exchanges to make up the difference. I suggest just testing then adding slowly the Mg and Cal while watching the Alk closely. Once you establish a daily dosing regime, then you could add that much to your dry salt mix. But I still prefer dosing liquids using a dosing pump. Never add anything until you are sure you have a accurate test showing what's lacking.


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[jeffaquarius]

The alk on your last reading is ok but you need to raise your mag first to at least 1300 before raising your calcium. I notice your alk fluctuates a lot. When it drops to 7 the balancing of the other would be difficult. In other words, maintain 9 dkh before dosing mag and calcium. Raising salinity would also help raising the values of trace elements and minimize dosing.