How much calcium & magnesium

[Tonyball]

Hi I've just brought some caso4 & mgso4 powder for raising my GH of ro water..

I change 50l per week...

So when mixed in a 500ml bottle of water 1 mil per 50l adds 0.5mg/l magnesium

And 1mil per 50l adds 0.6 mg/l calcium

I want to make the 50l of ro water a GH of around 6

How much of each in mil? do I need to add to achieve that GH of 6

I haven't a clue 😄

Thanks I'm advance

 

[Nick potts]

Have you already mixed up the solutions? You may have a hard time dissolving the CaSO4 as it's not very soluble.

I would just add the dry powders to your RO water, about 18-20 grams of each will get you roughly there, but it will depend on what ratio of cal to mag you want.

 

[Tonyball]

Have you already mixed up the solutions? You may have a hard time dissolving the CaSO4 as it's not very soluble.

I would just add the dry powders to your RO water, about 18-20 grams of each will get you roughly there, but it will depend on what ratio of cal to mag

 

[Tonyball]

I haven't mixed it yet.. surely 18g of each is to much for 50l of ro water?

 

[_Maq_]

May I ask you why do you want to make RO water hard?

 

[Tonyball]

Because ro water has a gh of 0.. I was using seachem equilibrium but have decided to mix my own

 

[_Maq_]

Because ro water has a gh of 0..

I was not asking about RO water. I know what it is.
I've asked why do you want to make it hard?

 

[Tonyball]

For the plants it's heavily planted..plus lots of shrimp

 

[Wookii]

Because ro water has a gh of 0.. I was using seachem equilibrium but have decided to mix my own

I think what @_Maq_ is trying to ask is why you are targeting GH6?

For the plants it's heavily planted..plus lots of shrimp

The plants don't need it, they are fine on a much lower GH target, but the shrimp certainly do. Depending on the shrimp you could drop it a bit, maybe GH4-5.

To echo @Nick potts point, CaSO4 is fairly difficult to dissolve, you'd be better with CaCl2 (Calcium Chloride).

 

[erwin123]

why not save money by mixing RO water and tap water?

 

[Tonyball]

My tap water is unusable.. It'd ro water only

 

[Hanuman]

Sounds pretty reasonable to add some minerals to RO water @_Maq_ . Not sure why that question.

@Tonyball The way you want to do it is not possible as you will get into solubility limits as advised by @Wookii . Here are the numbers:

You can see we are far exceeding the solubility limits if you prepare a solution and then dose 1ml. I would recommend you either dry dose instead or increase the dosage and use CaCl2 instead of CaSO4 as @Wookii suggested:

I am unsure if both can be mixed together in the same container though. Can anyone confirm this?

 

[Tonyball]

I think what @_Maq_ is trying to ask is why you are targeting GH6?



The plants don't need it, they are fine on a much lower GH target, but the shrimp certainly do. Depending on the shrimp you could drop it a bit, maybe GH4-5.

To echo @Nick potts point, CaSO4 is fairly difficult to dissolve, you'd be better with CaCl2 (Calcium Chloride).

I've already brought the stuff, just need to know the correct amounts to add.. ?

 

[Hanuman]

I've already brought the stuff, just need to know the correct amounts to add.. ?

I posted above the numbers but you can use the IFC calculator to tweak things around

 

[Tonyball]

Sounds pretty reasonable to add some minerals to RO water @_Maq_ . Not sure why that question.

@Tonyball The way you want to do it is not possible as you will get into solubility limits as advised by @Wookii . Here are the numbers:
View attachment 202454
You can see we are far exceeding the solubility limits if you prepare a solution and then dose 1ml. I would recommend you either dry dose instead or increase the dosage and use CaCl2 instead of CaSO4 as @Wookii suggested:
View attachment 202455
I am unsure if both can be mixed together in the same container though. Can anyone confirm this?

Am confused I thought u said the other day to get cas04 and mgs04 and stop using seachem equilibrium because of the excess potassium ?

 

[Wookii]

I am unsure if both can be mixed together in the same container though. Can anyone confirm this?

Not sure if both are sulphates, whether it makes the solubility of CaSO4 worse still. They have to be in separate containers if using CaCl2 though, as the Ca immediately bonds with the SO4 and drops out of solution.

 

[Hanuman]

Am confused I thought u said the other day to get cas04 and mgs04 and stop using seachem equilibrium because of the excess potassium ?

You might want to read again what I said about solubility above. You said you wanted to prepare a solution with CaSO4 and MgSO4 and then dose that in the tank. It's not possible due to solubility limits. Or perhaps I mis read you.
The advice is to dry dose instead or use CaCl2 instead. You have multiple choices.

 

[Nick potts]

Am confused I thought u said the other day to get cas04 and mgs04 and stop using seachem equilibrium because of the excess potassium ?

cas04 and mgs04 are fine to use, you just won't be able to mix the cas04 in a 500ml container, it just won't dissolve, add the powders directly to your 50ltrs or RO and you'll be fine.

Sorry, my calcs where off, I did 50 gals, not liters, 4.5g of CaSO4 and 5g of MgSO4 will give you around 5.2 GH which is plenty for plants and shrimp, mine is much lower and my shrimp are doing fine, but i do feed a lot of mineral foods.

 

[_Maq_]

Sounds pretty reasonable to add some minerals to RO water @_Maq_ . Not sure why that question.

My question was meant 'why bother making RO water when your intention is to have it hard, anyway'.

 

[Nick potts]

My question was meant 'why bother making RO water when your intention is to have it hard, anyway'.

The point of RO, for me at least is to have more control over water parameters, as well as removing any unknowns that might be in my tap water, using pure RO water is not a good idea, especially if you have shrimp or other inverts that need minerals.