Dosing of Calcium

[GaspingGurami]

Hi, in my heavily planted tank with high light and high CO2 injection, I've also been dosing PMDD in the form of KNO3, KH2PO4, K2SO4 and MgSO4 and TE derived from LGA.

I am wondering if I need to dose calcium, and if I do, how much should I be dosing as a starter, and what do I need to look out so I can know when and how much to dose. Do you normally use some other fert as a proxy?

I was using coral chips, but they all seemed to have dissolved away, and so that is why I'm looking now at dosing calcium.

Your thoughts please.

[theodore]

If your fertilization regime is accompanied by regular water changes (e.g. 30-50% weekly), then you can safely skip dosing Ca and Mg. I dose 1.2-2ppm of Ca (via Ca(NO3)2) and 0.3-0.5ppm of Mg (via MgSO4) every week but that's cos I change water every 3-4 weeks.

If you suspect your tank is running low on Ca (test your GH), the easiest way is to use coral chips and skip MgSO4.

[juggler]

Coral chips (especially those with broken shells) have more than enough Ca and Mg for your tanks. You can continue to use them and not to worry about extra dosing.

[budak]

I have stopped dosing K2SO4 and MgSO4 and have been dosing Seachem Equilibrium for the past months. If I gauge correctly, this provides sufficient K (there's enough K from KNO3 as well), Ca, Mg, Mn and some Fe to go with your KNO3 (keep NO3 dosing on the high side, plants guzzle it quickly), PO4 and LGA. I dose about a flat tablespoonful each week for my 250 litre tank. Mineral balance is a rather new area for many aquarists, but there's a good thread on this (and why so many fish/shrimp succumb even when all else is fine) here

[GaspingGurami]

Thanks for all your replies. I like the idea behind Equilibrium. Saves the trouble of getting the correct ratio for GH. Went down to NA to get a bottle but none in stock, so I reverted to good ol coral chips.

[Lme]

hi all,

read this thread regarding calcium, can i use calcium carbonate? do any of you know how much should i dose this CACO3? i have them in powered form, from Dr malick..

Thanks
Jabin

[theodore]

[quote:38ebab82e0="Lme"]can i use calcium carbonate?[/quote:38ebab82e0]
Yes, you can. After all, I expect most, if not all, of the Ca from coral chips to come from CaCO3.

do any of you know how much should i dose this CACO3?

Nope but you can do your own calculations and post them for us to verify if you are not sure.

[Lme]

hi hi

i put 1 teaspoon of calcium carbonate into 500ml of water and then dose about 20ml of the solution into my 3ft tank. this dosing is done on a daily basis.

would this be too much?

Thanks!!

[theodore]

[quote:342414e3="Lme"]i put 1 teaspoon of calcium carbonate into 500ml of water and then dose about 20ml of the solution into my 3ft tank. this dosing is done on a daily basis.
[/quote:342414e3]

How did you arrive at these numbers???

Since you didn't provide the bulk density or any info that can allow us to determine how much CaCO3 1tsp will yield, lets assume it to be 1g/cm3. Each tsp will then give you 5g of CaCO3, or 2g of Ca.

Assuming your tank volume to be 190L (since you did not did not give us this piece of info as well), every 20mL of your solution will add 0.42ppm of Ca.

This is too much Ca IMO but you will have to decide that for yourself. Every tank is different - my tank can't use Ca this fast doesnt mean yours can't.

[Plantbrain]

For fast dissolving GH:
MgSO4
CaCl2

CaCO3 powdered works placed in a hidden place and is added to as it dissolves away.

CaCO3 causes the KH to rise also!
This will make the CO2 less than you think if you measure just the pH.

Regards,
'Tom Barr

I did not vote for Bush!

[Lme]

thanks!!

[dx]

[quote:499c8044f3="Lme"]hi hi

i put 1 teaspoon of calcium carbonate into 500ml of water and then dose about 20ml of the solution into my 3ft tank. this dosing is done on a daily basis.

would this be too much?

Thanks!!
[/quote:499c8044f3]

i think calcium carbonate hardly dissolve in water. Is your bottle water cloudy? I am thinking calcium carbonate will remain at the bottom of the bottle, so you have to shake the bottle well before dosing. Am I right?

[Lme]

[quote:790dad40e1="dx"][quote:790dad40e1="Lme"]hi hi

i put 1 teaspoon of calcium carbonate into 500ml of water and then dose about 20ml of the solution into my 3ft tank. this dosing is done on a daily basis.

would this be too much?

Thanks!!
[/quote:790dad40e1]

i think calcium carbonate hardly dissolve in water. Is your bottle water cloudy? I am thinking calcium carbonate will remain at the bottom of the bottle, so you have to shake the bottle well before dosing. Am I right?[/quote:790dad40e1]

ya i shake the bottle first before dosing...

[GaspingGurami]

I think I put in too much coral chips into the Eheim

Every day, my kh increases by 2 degrees, the GH does the same rate of increase too.

Before putting in the coral chips, my kH was 4 degrees and GH 11 degrees. Without adding any baking soda nor magnesium sulfate, the kH increased to 6 degrees and GH increased to 14.5 degrees, 24 hours after the coral chips are introduced. Thereafter, the rate of increase is 2 degrees per day.

My question is,
1) how long at this rate will kH and GH continue to rise?
2) will it come to a point (while there is still coral chips left) where hardness will stop increasing or slow down?
3) Instead of testing, can I assume that if I change 50% of the water, will kH and GH values drop by 50%?

[vinz]

If your GH is at 11, you have enough Ca. What is prompting you to think that your tank is low on Ca?

[vinz]

1) & 2) No idea.

3) Yes, only if the water you add back has 0dGH. Our tap water is suppose to be at about 3dGH, so your final GH should account for that.

Also, how much does your plants use up between water changes?

[GaspingGurami]

[quote:1714d617="vinz"]If your GH is at 11, you have enough Ca. What is prompting you to think that your tank is low on Ca?[/quote:1714d617]

I never had the habit to check on GH in the past as I have a few pieces of coral chips mixed with the gravel. For good measure, I'd dose magnesium sulfate, after a bout of deformed, pale leaves, but with green veins.

One day, I noticed the coral chips have melted away (or smaller than a toothpick) I measured the GH and found it to be 11 degrees. I'm assuming that the hardness here is coming from my magnesium than the calcium.

I'm not sure how to estimate GH uptake. I figure, having some coral chips and dosing some magnesium every waterchange is enough. Can you advise the correct way to gauge requirement and so dose accordingly?

Thanks

[vinz]

To estimate GH uptake, just do a measurement after an Mg and Ca dose. Then measure again before you dose Mg and Ca again. Then you'll know how much GH had dropped.

But if you have an in-tank source of GH, then this measurement won't work unless you know how much GH the intank source adds, and account for it.

What is your tank regime? I.e. how much of what and when do you add, plus your water change schedule?

[GaspingGurami]

[quote:895725fd57="vinz"]To estimate GH uptake, just do a measurement after an Mg and Ca dose. Then measure again before you dose Mg and Ca again. Then you'll know how much GH had dropped.

But if you have an in-tank source of GH, then this measurement won't work unless you know how much GH the intank source adds, and account for it.[/quote:895725fd57]
You're right. With the new coral chips, there is no way to measure GH uptake.

[quote:895725fd57="vinz"]What is your tank regime? I.e. how much of what and when do you add, plus your water change schedule? [/quote:895725fd57]
Effective volume: 24Litres
Photoperiod: 10 hours, 12 WPG.
CO2: 36-56ppm during photo period.
Ferts added daily with water top-up: LushGroAqua, 2ml
Loose ferts: KNO3 : K2SO4 : MgSO4 to make a total of 4.5 : 7.6 : 2.1ppm
Plant load is very dense, light barely reaches to the bottom even at 12 WPG.
Fish load is also very high, with lots of feeding, I have around 5-10ppm PO4.

Ever since I've added the coral chips, I've stopped the MgSo4. However, the E. oriental leaves are getting pale and yellowish with green veins, so I think I'll resume the Mg for a couple of days to see how it goes.

Water change: weekly 12L