Ca, Alk, Mag supplementing


New member
ok, so I'm new to the hobby and found out that I was not testing the most important level. Calcium, Alk, and Magnesium. Of course and others like Salinity, Ammonia, Nitrites, Nitrates, etc.
So I bought the Red Sea Reef Foundation® Pro Test Kit and tested my levels and they were as followed:
Calcium: 850
Magnesium: 1440
Alkalinity: (Meq/L=5 & dKH=14 = 250 ppm)

I know, I know they are way too high.:eek1:

So then I went and bought the Red Sea Reef Foundation ABC Reef Supplement Multipack
The problem is that I dont really understand how I'm supposed to use it. I see the dosing chart and it makes sense but do you add the supplement whether its too high or even too low?
I see that I need to test again after four days to see how much I have dropped and then divide the difference by 4 and dose that amount every day until I reach my desired level. Do I have that correct?
I think that I need to add the supplements to decrease my levels but do I add them if I need to increase my levels too? Thats what I dont understand?
I hope this all make sense and I would appreciate any feed back.
Thank in advance.


Premium Member

800 ppm of calcium seems very high without dosing. I'd try testing some freshly-mixed saltwater to see how that measures up. We see a lot of problems with test kits.


New member
That calcium number seems incredibly high, you're using almost 2ml's of titrant.
Are you using 10ml of water instead of 5?

Watch this Red Sea video to ensure you're doing the test right.


New member
The instructional video's available on youtube are very good. Also, make sure you're reading the syringe from the bottom of the plunger, and not the top of the fluid. The other caveat here is that the Red Sea kit calculation is determined by taking your end point reading from the plunger in the syringe and deducting it from the 1mL you started with, to determine how much of the titrant was used, i.e. if the reading on the syringe is .37 you used .63, which is the number you need to determine your reading. It isn't hard, but you have to do the math, and I see it as an area for potential human error. The Salifert kit just gives you the reading without the user having to do any additional calculations.