Calcium/magnesium?

[JoeQ]

Is there a good natural way to add both calcium combined with magnesium? I know crushed coral for calcium but what about magnesium? Should i look into adding a small amount of epson salt to see if that improves deficiencies or will that be harmful to fish/snails? 

[Mmiller2001]

Epsom salts is fine. Just make sure it's 100% MgSO4 and no scents added.

[JoeQ]

On 5/15/2022 at 2:07 PM, Mmiller2001 said:

Epsom salts is fine. Just make sure it's 100% MgSO4 and no scents added.

Is there an amount you recommend per 10 gallons? Im more looking for a fertilizer dose rather than a medical dose used with fish

[Mmiller2001]

Well, do you know your GH and are you using tap water? You may not need to add any if your tap water has some in it. A water report should let you know the ppm. 

Usually, Ca and Mg are kept in ratios. 4:1, 3:1 and 2:1 are commonly used. But I would check your water report first.

[JoeQ]

Im not at my tank right now to test but usually my gh is 75 after water change and stabilizes at 150 on average. My kh is low, especially after water change. I try to keep it at 80 through adding Crushed coral and spot dosing baking soda.

Edited May 15, 2022 by JoeQ

[Mmiller2001]

You might be able to pull the water report off their website.

[Seattle_Aquarist]

On 5/15/2022 at 10:45 AM, JoeQ said:

Is there a good natural way to add both calcium combined with magnesium? I know crushed coral for calcium but what about magnesium? Should i look into adding a small amount of epson salt to see if that improves deficiencies or will that be harmful to fish/snails? 

Hi @JoeQ

I do not recommend the use of coral, crushed shells, or any other form of limestone which are all forms of calcium carbonate for planted tanks.  Why?  Because not only does it increase calcium levels, it increases the dKH (aka pH) and dGH and there is no way to know how much is being added so it is easy to exceed target levels.  What are the target levels you ask?  Typically I try to maintain about 20 ppm of calcium (CA) and 5-6 ppm of magnesium (Mg).  Now, how do I increase the local Seattle water (pH@7.0 (degassed). dKH@1.0 ppm, dGH@2.0-3.0 ppm, Ca@7-8 ppm, Mg@0.3 - 0.9 ppm -  notice how little Mg is in my local water) without increasing my pH?  I use calcium sulfate to increase the calcium level and magnesium sulfate (Epsom salt) to increase the magnesium level.  Note that neither of the two things I add are carbonates so there is no effect on my pH. 

Why I am concerned about my pH?  Because the higher the pH the more difficult it becomes for plants to uptake important nutrients.  If you look at the chart below as the pH increase above 7.5 most nutrient availabilities have started to drop off and are basically unavailable in some cases.  That is why I constantly discourage the use of coral or any form of limestone / calcium carbonate in planted tanks.


As for your question as to if magnesium should be added to the tank?  It will only help if a lack of magnesium is indicated which usually shows up as interveinal chlorosis in older leaves, leaf margins curling upward or downward with puckering, and in some cases premature loss of older leaves.  Stem plants are also more susceptible to fungus infection (stem rot).  -Roy 

[Torrey]

@Seattle_Aquarist you just explained my mistake. 

I need to find calcium sulfate for my snails. My nerites (both 11+ years old now) started showing pitting in the last month... as I got my TDS reduced to eliminate cyanobacteria. 

BGA is gone, but snails are looking a little rough.

Plants show Mg & iron deficiencies (you already explained the iron issue, and new growth is looking much better)

[JoeQ]

I'm actually more confused than ever!! This usually happens when I think 'I frigging got it! My deficiency looks like calcium, my calcium is great tho (about 4.5 dKH) so this in turn would be a magnesium deficiency wouldn't it? Cause don't you need the magnesium to up take calcium? 

Edit: this picture is from a plant planted in black diamond blasting sand. Which doesn't appear to be absorbing nutrients from the water colum like my primary substrate which is eco complete

Edited May 16, 2022 by JoeQ

[Seattle_Aquarist]

On 5/16/2022 at 11:22 AM, Torrey said:

@Seattle_Aquarist you just explained my mistake. 

I need to find calcium sulfate for my snails. My nerites (both 11+ years old now) started showing pitting in the last month... as I got my TDS reduced to eliminate cyanobacteria. 

BGA is gone, but snails are looking a little rough.

Plants show Mg & iron deficiencies (you already explained the iron issue, and new growth is looking much better)

Hi @Torrey

I buy my calcium sulfate on Ebay in 5# bags from AC Chemical on Ebay for about $7.00 plus shipping.  Keep in mind that it will make the water cloudy for a few hours after dosing, no damage to livestock or plants.  It doesn't take a lot, 1/4 teaspoon will increase the amount of calcium in a 10 gallon tank by 5 ppm.  -Roy

[Mmiller2001]

On 5/16/2022 at 12:59 PM, JoeQ said:

I'm actually more confused than ever!! This usually happens when I think 'I frigging got it! My deficiency looks like calcium, my calcium is great tho (about 4.5 dKH) so this in turn would be a magnesium deficiency wouldn't it? Cause don't you need the magnesium to up take calcium? 

Edit: this picture is from a plant planted in black diamond blasting sand. Which doesn't appear to be absorbing nutrients from the water colum like my primary substrate which is eco complete

GH is a combination of Calcium and Magnesium. So dGH tells us a total, but doesn't tell you a ratio or breakdown. You could have 4.5dGH made up of all Ca or all Mg or any combination of both. If you are using tap water, get a water report. It will most likely tell you the Ca and Mg percent or ppm. Otherwise, you will need to test for Ca and Mg. Guessing will be problematic.

[Seattle_Aquarist]

On 5/16/2022 at 11:59 AM, JoeQ said:

I'm actually more confused than ever!! This usually happens when I think 'I frigging got it! My deficiency looks like calcium, my calcium is great tho (about 4.5 dKH) so this in turn would be a magnesium deficiency wouldn't it? Cause don't you need the magnesium to up take calcium? 

Edit: this picture is from a plant planted in black diamond blasting sand. Which doesn't appear to be absorbing nutrients from the water colum like my primary substrate which is eco complete

Hi @JoeQ,

You are correct, black diamond blasting sand is inert, it contains no nutrients and has no effect on the uptake of nutrients.  I see leaf puckering but it is hard to tell from the picture if there is any leaf margin curling or not.  Leaf puckering is a symptom of insufficient available magnesium (Mg) which can but caused by a number of conditions - the two most common are not enough magnesium being dosed or too much of another nutrient (like calcium) effecting the uptake of magnesium by the plant.  -Roy

Edited May 16, 2022 by Seattle_Aquarist

[JoeQ]

On 5/16/2022 at 5:14 PM, Mmiller2001 said:

GH is a combination of Calcium and Magnesium. So dGH tells us a total, but doesn't tell you a ratio or breakdown. You could have 4.5dGH made up of all Ca or all Mg or any combination of both. If you are using tap water, get a water report. It will most likely tell you the Ca and Mg percent or ppm. Otherwise, you will need to test for Ca and Mg. Guessing will be problematic.

Still looking, i can't find one online. I'll probably have to stop by the water company to get it. 

On 5/16/2022 at 5:21 PM, Seattle_Aquarist said:

Hi @JoeQ,

You are correct, black diamond blasting sand is inert, it contains no nutrients and has no effect on the uptake of nutrients.  I see leaf puckering but it is hard to tell from the picture if there is any leaf margin curling or not.  Leaf puckering is a symptom of insufficient available magnesium (Mg) which can but caused by a number of conditions - the two most common are not enough magnesium being dosed or too much of another nutrient (like calcium) effecting the uptake of magnesium by the plant.  -Roy

Here is another pic, i was going to burry a small amount of epson salt to see if i can get some root availability 

[Mmiller2001]

On 5/16/2022 at 3:24 PM, JoeQ said:

Still looking, i can't find one online. I'll probably have to stop by the water company to get it. 

Call them, simply ask what ppm Ca and Mg is in your water.

[JoeQ]

On 5/16/2022 at 5:26 PM, Mmiller2001 said:

Call them, simply ask what ppm Ca and Mg is in your water.

Cool thanks!