Amount of Ca and Mg for my tank

rthomas

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Oct 25, 2007
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Hi all,
I have a tank that can take up about 650 L of water. I used 7 bags of AS and that consumed 9L (volume of each bag of AS) x 7 = 63L. The rocks and driftwood took roughly another 10L the most.

So I am left with about 650 - 63 - 10 = 577 Liters of water in my tank.

I could work out the other EI components (NPK) but am kinda lost with the amount of Calcium and Magnesium that I should dose for that much of water. I have Calcium Sulphate (Plaster of Paris) and my Magnesium source is Epsom salt.

I would appreciate if someone could let me know how many teaspoons of Calcium Sulphate and Epsom salt that I should add after every 50% WC. Thank you in advance.
 

Tom Barr

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Jan 23, 2005
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Question is, what's the Ca and Mg of the tap water?

Then you can figure, plants will not use much more than 10ppm of Ca and 3-5 ppm of Mg I'd imagine per week under extreme high rates of growth.

I generally suggest with most GH's, to add another 1-2 degrees of GH booster to the routine after the water change.

Regards,
Tom Barr
 

rthomas

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Oct 25, 2007
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Tom Barr;26913 said:
Question is, what's the Ca and Mg of the tap water?
Unfortunately the water company here is uncooperative to give that sort of detail. But we have soft water here with GH around 1.5

Then you can figure, plants will not use much more than 10ppm of Ca and 3-5 ppm of Mg I'd imagine per week under extreme high rates of growth.
If I am targeting, say, 6ppm Ca and 1.5ppm Mg, what would be the amount in teaspoons would that be. Yes, I have only measuring spoons but not gramme scale :(

On top of that, Tom, is 6ppm Ca with 1.5ppm Mg an acceptable concentration. If okay, then I will increase it bit by bit when growth becomes better.

I generally suggest with most GH's, to add another 1-2 degrees of GH booster to the routine after the water change.
I wish we have that available locally :(
 

Tom Barr

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Gh booster is legal in all 50 states, Canada, and mexico:)

Cheap too.

Add about 1:2 parts MgSOI4/CaSO4, you can us ea dosing cal to get precise measures, but 1/2 teaspoon per 80 liters should be more than enough, remember that they have 2 H2O's and 7 H2O's(Hydrated salts).

Yes, 6 and 1.5 ought to fine 2x a week.
There are no bad effects, only good ones as you add more than say 1-2 GH's to the water, up to at least 7-10 range, you get better colors.

Regards,
Tom Barr
 

chiligirl

Junior Poster
Jan 15, 2008
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Here's a related question: If my tap water has 20ppm Ca and 1.6ppm Magnesium on average, do I need to dose GH booster?

I've got a 20gallon with fluorite substrate, pressurized CO2 (keeps my drop checker a steady green) and 130 W of light over it. Plants are growing great. So's the algae *sigh*. I'm struggling with green dust algae and the dreaded clado. I'm guessing it's from fluctuating nutrient levels - I haven't been doing proper EI dosing. I've just been throwing the ferts in once per week, after the water change. I'm beyond tired of testing the water, so I'm thinking I'll adopt the EI method, and just dose every other day and do that big water change once per week.

I'm rambling...

Anyhow, is that enough Ca and Mg? If it's not enough of the latter (which I suspect), can the plants pull the Ca from the tap water, and I can top up the Mg with epsom salts?

Other stats on the tank:
pH is around 7.3
using a Magnum HOT filter (love it!) rated 350gph flow. I've slowed it down a bit by putting a sponge over the intake
substrate is fluorite as mentioned, mixed with geosystems gravel (same shape and color, just a sort of inert clay gravel)
hardscape is some natural river wood and river rock (which I boiled the heck out of!) from the Fraser River.
Tank temp is room temperature, about 74F
CO2 is running 24/7 at about 2bps (drop checker is green to yellow-green)
plants are a bit of this and that: ludwiga, rotala, cabomba, some crypts (including parva), some vals, hairgrass, a nice red plant who's name I forget, and some odd and end stems I pulled out of my 90 when I switched it to low light
fauna is a pair of GBR, a bunch of platies, some cherry barbs, panda cories, couple of otos, a bamboo shrimp, a handful of tiger shrimp and 8 amanos.
 

VaughnH

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Jan 24, 2005
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If you cut the light on that 20 gallon tank from 130 watts to 65 watts - remove one bulb - your algae problems will be a lot easier to solve. If you raise the light fixture a few inches above the tank, it gets easier still. You really have far too much light now. Then switching to the EI method will do a lot of good, as would making sure you have good water circulation all over the tank - all of the leaves should be in motion.
 

chiligirl

Junior Poster
Jan 15, 2008
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the lights are mounted about 7" above the water's surface (it's an open top, rimless tank). And the tank is more like 22G (it's a funny size), not that it matters much. 6.5 wpg is high light, I know, but I didn't think it was too high? If I drop it down to 65W, that's just 3wpg, which is only medium light I thought? The tank doesn't look unnaturally bright - it looks quite nice, IMO. Except that I'm having to wipe down the glass every couple of days.
 

Graham

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Mar 10, 2005
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IMO, 65 watts over a tank that size should be able to grow about anything quite well. Mind your CO2, ferts and water changes and it'll grow in just as good as it would with twice the lighting.
 

chiligirl

Junior Poster
Jan 15, 2008
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BC, Canada
I should've clarified - I've only got the full wattage on for a 3 hour burst. For the remaining 5 hours of my 8 hour photo period, it's only 65W.
 

ThanhVu

New Member
Mar 28, 2019
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Vietnam
hello
-I have an 18 liter tank
-How much Ca, Mg must be added when changing water to get 2GH?
-I use CaCl2.2H2O ..... MgSO4.2H20
 
Last edited:

BettaBeGood

Member
Oct 15, 2020
59
16
8
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canton m.i
Question is, what's the Ca and Mg of the tap water?

Then you can figure, plants will not use much more than 10ppm of Ca and 3-5 ppm of Mg I'd imagine per week under extreme high rates of growth.

I generally suggest with most GH's, to add another 1-2 degrees of GH booster to the routine after the water change.

Regards,
Tom Barr
Hello Sir. It is finally my pleasure to introduce myself to a planted tank LEGEND. I HAVE A 40BREEDER. Dutch scape heavily loaded. Im having a hard time growing Pogostemon Stallata. I have saw your post on this specific plant.. i have 122watts of leds hanging 10 to 11 inches above water surface. I have auqa soil and pressurized co2 while dosing Nilocg Diy E.I mix with ex iron. Im having bad stunting and leaf curl.. which leads me to calcium deficiency.
1. 40BREEDER
2. 122watts of led light 11inch over h20 surface
3. Fluval stratum with root tabs
4. Pressurized co2
5. Nilocg D.I.Y E.I MIX +IRON
6. Tank temp 74degrees
7. 8hr photo period
8. Gh5
9. Kh3.5 maybe 4
10. Ph 6.5 6.6
Is there anything you see wrong?? Plz help
I did add seachem equilibrium to my tap. I added 16grams on my last h20 change day and tested gh it was 9gh kh still 3.5 I have seen positive leaf morphology since dosing equilibrium. But is there anything else I can do? Ty for your help Sir.

16028101020205740457503622828004.jpg
 

BettaBeGood

Member
Oct 15, 2020
59
16
8
36
canton m.i
Hello Sir. It is finally my pleasure to introduce myself to a planted tank LEGEND. I HAVE A 40BREEDER. Dutch scape heavily loaded. Im having a hard time growing Pogostemon Stallata. I have saw your post on this specific plant.. i have 122watts of leds hanging 10 to 11 inches above water surface. I have auqa soil and pressurized co2 while dosing Nilocg Diy E.I mix with ex iron. Im having bad stunting and leaf curl.. which leads me to calcium deficiency.
1. 40BREEDER
2. 122watts of led light 11inch over h20 surface
3. Fluval stratum with root tabs
4. Pressurized co2
5. Nilocg D.I.Y E.I MIX +IRON
6. Tank temp 74degrees
7. 8hr photo period
8. Gh5
9. Kh3.5 maybe 4
10. Ph 6.5 6.6
Is there anything you see wrong?? Plz help
I did add seachem equilibrium to my tap. I added 16grams on my last h20 change day and tested gh it was 9gh kh still 3.5 I have seen positive leaf morphology since dosing equilibrium. But is there anything else I can do? Ty for your help Sir.

View attachment 16323
I also have 30 to 40ppm of Co2
 

BettaBeGood

Member
Oct 15, 2020
59
16
8
36
canton m.i
Question is, what's the Ca and Mg of the tap water?

Then you can figure, plants will not use much more than 10ppm of Ca and 3-5 ppm of Mg I'd imagine per week under extreme high rates of growth.

I generally suggest with most GH's, to add another 1-2 degrees of GH booster to the routine after the water change.

Regards,
Tom Barr


So if my 40 gallon breeder planted tank dgh is 7 7.5 and has a magnesium deficiency how much should I dose of Magnesium epson salt i do 50% WC WEEKLY 20gal replace of h2o