Magnesium dosing

Dmac

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Right now I've got a 120 that consumes about 40ml of alk/calc daily. I keep trying to find out roughly how much mag I should dose weekly to keep up so I'm not having to make huge adjustments when I realize it's gotten low. Best I could find was Randy-what's-his-name saying 1ml of mag for every 6ml of alk. Does anybody dose like this?
 

bg2311

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You could test for magnesium, wait a few days, then test again. Divide the change +/- by the number of days to see if you need to increase or reduce the dosage to hit your target range. Aiming for ~1,300?
 

Dmac

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I thought about that. The problem is that my red sea test kit doesn't seem to be even close to accurate enough for me to use it as a baseline over that short of a period of time.
 

bg2311

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I thought about that. The problem is that my red sea test kit doesn't seem to be even close to accurate enough for me to use it as a baseline over that short of a period of time.
PXL_20210610_165614511.jpg

This one is pretty easy to use. With mag you're usually looking for an acceptable range (especially with a color changing titration test kit). No need to chase exact numbers.
 

Dmac

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Yeah, I saw BRS recommended that one. Maybe I'll give it a try. My results from my Red Sea are always all over the place
 

bg2311

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Yeah, I saw BRS recommended that one. Maybe I'll give it a try. My results from my Red Sea are always all over the place
We started with the Red Sea kit initially (calc/alk/mag) and moved to Hanna colorimeter testers (worth the investment IMHO) for alk/calc/phos. Since they don't make a one for magnesium yet, we went with the Aquaforest and found it a bit easier to tell when the color change happens. I usually put my phone's flashlight LED on and set the phone down with the light pointing up into the bottom of the testing vial. It makes it easier to see the color transition. Even if you don't get it perfect, you still get a good idea of the range that it's in which I've found to be enough for magnesium.
 

Dmitri

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I also use Red Sea test kit for magnesium
I try to keep it at 1440 level, gives little bit of a safety buffer and helps with slowing down algae growth too

Other test kits by Red Sea I found to be not as good / dependable / easy to use as Hannah for alk / phosphates or tropical marine for nitrates
 

Dmac

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Yep, I'm all over Hannah for alk and phosphates. My calcium red sea has always been good.
 
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