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Discussion Starter · #1 ·
Very long story short, I had a suspicion that my very hard well water was lacking Mg. I borrowed a Mg test from a reefer friend of mine, and no matter what I did, I couldn't get it to register any Mg at all. I then ran a test with a known Mg solution, and got the reading I expected.

This morning, I did my normal weekly WC and dosed Mg to be at a 3:1 ratio with my CA.

I just checked my tank (an hour before lights off), and everything was pearling so hard it looked like a tank full of club soda. I've only seen this immediately after a water change, but this was almost 12 hours after my WC this morning.

If my Mg was really that close to zero, could suddenly adding it cause that much of a change in just 1 day, or is it just a coincidence?
 

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Hi
Can you give us more specific values of Ca and Mg? Because it is rather difficult to know what is involved with a tester designed to maintain reef aquarium’s 1300 ppm of Mg when planted aquariums need only about 5 ppm.

Also, if MgSO4 is poured into heavily saturated high CaCO3 and CO2 water, it will expel lots of CO2.
 

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Discussion Starter · #3 ·
My Ca measured around 80ppm, and the Mg was unmeasurable.

The test kit worked by adding 2 reagents to the water, then adding a third reagent, drop by drop, until the color changed from Magenta to Blue. In my water, the sample was blue without adding any of the third reagent. As a control, I made a solution of 10ppm Mg using RO water, and that sample required me to add some of the third reagent in order to change to blue.

This led me to believe that my water from the tap has somewhere between 0ppm and 10ppm of Mg. With my water change this morning, I added 20ppm Mg, which would bring me to 20-30ppm Mg.

I know it's not perfect, but that was my methodology.

As far as the Mg reacting and creating CO2, I didn't notice a difference in my ph compared to the day or weeks before. I currently run a ph drop of about 1.3 with my CO2 on (degassed = 7.8, CO2 on = 6.5). My ph was steady at 6.5 when I saw the intense pearling, which isn't any different than normal days.
 

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Interesting
Now you have 80 ppm Ca and 20 ppm Mg, that is 11 Ca-dGH, 5 Mg-dGH, 16 dGH total. Curious, what is your KH and what plants do you grow?

If you want to turn your aquarium to guinea pig, you can follow the Marschner ratio described in @happi thread here. You only need to have 32 ppm Mg and 160 ppm of K.
 

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I have a Red Sea Magnesium Pro test kit which sounds similar to yours (2 reagents).
What I did with mine is as follows;
Original Test
* 2ml tank water + 5 drops A and + 5 drops B. Then you add Titrant until color change. Each drop = 20ppm MG

Revised Test
* 10ml tank water + 25 drops A and + 25 drops B. Then you add Titrant until color change. Each drop = 4ppm MG
 

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Curious, what is your KH and what plants do you grow?
Kh is around 8. Right now, I'm growing HC Cuba, DHG, Eleocharis Vivipara, Ludwigia sp. Super Red, and Anubias Nana Petite. The thing that made me question the Mg was dark red veins, but pale orange flesh on the Ludwigia.

I have a Red Sea Magnesium Pro test kit which sounds similar to yours (2 reagents).
What I did with mine is as follows;
Original Test
* 2ml tank water + 5 drops A and + 5 drops B. Then you add Titrant until color change. Each drop = 20ppm MG

Revised Test
* 10ml tank water + 25 drops A and + 25 drops B. Then you add Titrant until color change. Each drop = 4ppm MG
Yupp, that's the one. I'll have to get my buddy back over here to try this. It would be nice to get an actual number instead of "<10pmm"

If you want to turn your aquarium to guinea pig, you can follow the Marschner ratio described in @happi thread here. You only need to have 32 ppm Mg and 160 ppm of K.
I'll be honest, every time I try to read through that thread, I die a little inside. There is so much great information, but it's just too dense for my ADD to handle. I take bits and pieces, a little at a time, and see what it does to my tank.
 

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Original Test
* 2ml tank water + 5 drops A and + 5 drops B. Then you add Titrant until color change. Each drop = 20ppm MG
Are we talking about the same Red Sea Mg test kit?

The manual says:
0.01 ml = 20 ppm Mg

Therefore:
1 drop = 100 ppm Mg (not 20 ppm)

Because:
1 ml = 20 drops
0.05 ml = 1 drop
 

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Are we talking about the same Red Sea Mg test kit?

The manual says:
0.01 ml = 20 ppm Mg

Therefore:
1 drop = 100 ppm Mg (not 20 ppm)

Because:
1 ml = 20 drops
0.05 ml = 1 drop

Yes, now that I got my readers out and looked - 0.01 ml = 20 ppm Mg is correct. Probably why I had a insulin syringe (very tiny syringe) in the box so I could measure 0.01 ml. Sorry, was last used in 2017 sometime so I guess I forgot one of the steps.
 

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Discussion Starter · #10 ·
I would not come to any conclusions from something that happened for one day.

Give it weeks then see if it's still the same.

Out of curiosity, what is your dGH?
That's kind of what I figured. I was just thinking that if there was a nutrient that was completely bottomed out, maybe there could be a drastic change after adding it.

I'll check my GH tomorrow. Should I check the water from the tap, or the tank water now that I've added Mg?
 

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That's kind of what I figured. I was just thinking that if there was a nutrient that was completely bottomed out, maybe there could be a drastic change after adding it.

I'll check my GH tomorrow. Should I check the water from the tap, or the tank water now that I've added Mg?
Why not both? Wanted to see if that 80 Ca reading matched up with your GH reading, and then again after you've added Mg.
 

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Discussion Starter · #12 ·
That's kind of what I figured. I was just thinking that if there was a nutrient that was completely bottomed out, maybe there could be a drastic change after adding it.

I'll check my GH tomorrow. Should I check the water from the tap, or the tank water now that I've added Mg?
Why not both? Wanted to see if that 80 Ca reading matched up with your GH reading, and then again after you've added Mg.
I'm going to have to get a Ca test kit, because the readings I got on my Gh don't make much sense if the Ca is at 80ppm. Just going by the number of drops, it took 10 drops to change from the tap, and 12 drops to change from the tank. Idk how much of that is the Mg I added, and how much is the 300lbs of Sieryu stone in the tank though...
 

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... 300lbs of Sieryu stone in the tank though...
If I had so much Seiryu stone with CO2 injection I would have Ca, GH, KH test kits ready and a TDS meter, before adding any Ca, Mg or KH. This stone leaches a lot of Ca and KH, and maybe also Mg. You need GH and Ca values to calculate Mg, then with KH and TDS you will see what to do.
 

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Discussion Starter · #14 ·
... 300lbs of Sieryu stone in the tank though...
If I had so much Seiryu stone with CO2 injection I would have Ca, GH, KH test kits ready and a TDS meter, before adding any Ca, Mg or KH. This stone leaches a lot of Ca and KH, and maybe also Mg. You need GH and Ca values to calculate Mg, then with KH and TDS you will see what to do.
This is one of the reasons I was thinking I would need to be adding Mg. I had ready that the stone would leech Ca and carbonates, but that it wouldn't leech much Mg. I also do pretty massive water changes to keep the TDS under control. My baseline ph is around 7.8ish after a water change, and it goes up to around 8 by the end of the week.
 

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I'm going to have to get a Ca test kit, because the readings I got on my Gh don't make much sense if the Ca is at 80ppm. Just going by the number of drops, it took 10 drops to change from the tap, and 12 drops to change from the tank. Idk how much of that is the Mg I added, and how much is the 300lbs of Sieryu stone in the tank though...
That actually makes sense.

80 Ca is about 11 dGH. Add some Mg and goes up a bit.

But that Sieryu stone is doing exactly what you don't want, adding KH.

In general, plants do better in lower KH water, and folks go to great lengths (RO Water) to lower or eliminate KH. You don't need or want higher KH.
 

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Discussion Starter · #16 ·
That actually makes sense.

80 Ca is about 11 dGH. Add some Mg and goes up a bit.

But that Sieryu stone is doing exactly what you don't want, adding KH.

In general, plants do better in lower KH water, and folks go to great lengths (RO Water) to lower or eliminate KH. You don't need or want higher KH.
I'm not adding any KH at all, aside from what's leeching from the stone. I'm also doing pretty massive water changes to keep the KH as low as I can without going to RO water. My KH has been pretty stable at 7.5 - 8 post water change. I think I've hit an equilibrium with my water changes vs rock leeching
 

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I'm not adding any KH at all, aside from what's leeching from the stone. I'm also doing pretty massive water changes to keep the KH as low as I can without going to RO water. My KH has been pretty stable at 7.5 - 8 post water change. I think I've hit an equilibrium with my water changes vs rock leeching
IMO your planted tank would be easier without those stones. You would have a lower and more stable KH, which is much easier to work with.

But other than the dGH/dKH, how is the tank doing overall these days? Any pics?

In general, messing around with dGH to get it right has small benefits compared to other things that might help.
 

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Discussion Starter · #18 ·
But other than the dGH/dKH, how is the tank doing overall these days? Any pics?

In general, messing around with dGH to get it right has small benefits compared to other things that might help.
I completely moved the tank and rescaped from my journal. I just put a pic a couple of messages back, but I really need to do a new journal. I have so many new quality of life improvements that I want to share 😃.

As far as trying to tweak the dGH, I'm not really that concerned with it. This post started because I was curious if adding Mg could have an immediate impact on plant health, because I saw some crazy pearling out of nowhere. The only thing I'm doing to "control" the GH is doing massive water changes. I think I will add a little Mg to my water changes to give a little to the plants, but other than that, I'm not that concerned. The tank is running beautifully, and I'm zeroing in on small things that could improve growth. Im pretty sure my well water is near zero Mg, so it needs to be added for the plants.
 
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