# When is Magnesium and Calcium necessary to dose?



## bsmith (Dec 13, 2006)

After looking at the fertilator I realized I have never dosed either of these by them self. I understand the TPN+ I use in my nano has it (Magnesium) but in my 37g where I dose KNO3, KH2PO4, K2SO4, Flourish Iron and Flourish there probly isnt too much in there. As far as the Calcium I dont think ANY thing I dose has it.

The main reson I have been doing more research on dosing is that I cant seem to get my needle leaf stellatus to color up yet, granted it isnt even half way up my 24" tall tank and this could be the problem but I just though I would be seeing some by now.

Thanks.


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## Seattle_Aquarist (Mar 7, 2008)

Hi bsmith782,

Here in Seattle we have very soft water, typically 1.0 DH. There are times that my plants exhibit signs of Ca or Mg deficiency, when they do I dose CaCl or MgSO4 (Epsom Salts). Here is a link to a site I use to help me diagnose nutrient deficiency or excess symptoms. Scroll about 1/2 way over and 1/2 way down. Hope this helps! http://www.finostrom.com.gr/images/aqua/fertilizers/map.htm


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## bsmith (Dec 13, 2006)

Nice chart. I am not showing any if the defficiency symptoms. I really am more or less just trying to fine tune the tank to get the best most luxurious growth I can get.

Post from TPT.

Well I feel kinda foolish (maybe my test kit is bad). Just got done testing and here are the results.

KH-1 (maybe less)
GH-6

Like I said I think the test kit (AP) is a year to six months old, dont know if they go bad. The tank also has AS I and is injected with with co2.

Comments, suggestions...



Seattle_Aquarist said:


> Hi bsmith782,
> 
> Here in Seattle we have very soft water, typically 1.0 DH. There are times that my plants exhibit signs of Ca or Mg deficiency, when they do I dose CaCl or MgSO4 (Epsom Salts). Here is a link to a site I use to help me diagnose nutrient deficiency or excess symptoms. Scroll about 1/2 way over and 1/2 way down. Hope this helps! http://www.finostrom.com.gr/images/aqua/fertilizers/map.htm


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## Seattle_Aquarist (Mar 7, 2008)

Hi bsmith782,

I grew up in St. Louis, and the water was pretty soft then too. It varied somewhat during the year since the primary water sources are the Missouri and Mississippi Rivers. I don't remember a problem with mineral deficiencies however.


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## bsmith (Dec 13, 2006)

I thought that adding a little (ca 1.5tsp mg .5tsp) per dosing (on macro days) would help with my pogostemon stallatus.


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## Seattle_Aquarist (Mar 7, 2008)

Hi bsmith782,

So I wandered over to TPT website and checked out Pogostemon stallatus. It seems to like medium low to low hardness with KH = 4 or less and GH = 5 or less. It does give some pretty detailed substrate suggestions here as well.
http://www.plantedtank.net/forums/myplants/68-Pogostemon_stellatus_Pogostemon_stellatus.html


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## bsmith (Dec 13, 2006)

So I have ben dosing the above mentioned levels for a week. My Kh is still 1 and my GH is still 12.5. What gives? Should I dose more Mg and less Ca???


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## Seattle_Aquarist (Mar 7, 2008)

Hi bsmith782,

What are you trying to raise, the Kh or Dh? To raise the Kh I add Bicarbonate of Soda (Baking Soda).


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## bsmith (Dec 13, 2006)

I thought that was what Ca was for. Also, I thought that plants really didnt care about KH. I have never experiences any wild ph swings.


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## zdam20 (Mar 8, 2009)

If your kh is 1 and your gh is 12 I'm guessing you should not have to dose any calcium or magnesium. My understanding is kh is carbonate hardness, caused by carbonate and bicarbonate. Gh is caused by mainly calcium and magnesium. If you get a calcium test kit (any salt water fish store should have one) you can calculate how much magnesium is in your water. you take the general hardnes number times 17.86. From this number subtract the product of the calcium ppm times 2.5. Divide the remander by 4.1 and you have the ppm magnesium in the water. I got this formula in the pps fertilizer forum. Like I said though with a gh of 12.5 I would think you've got plenty of calcium and magnesium.


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