MG:Ca Assistance please

[Disciple]

I have been having some trouble with my water parameters after over dosing on a product a few months ago.

I have slowly been working on my wp and have finally got them close to where I want them in my tanks, I just need some help to get it even closer to where I want it.

Tank 1's Wp is ph 6.6 gh6 kh1 Ca40 and the TDS is 170~ Currently the MG:Ca ratio is 2.79 - This is my divided tank holding PRL BB and Pintos

Tank 2's WP is Ph7.2 gh11 kh3 Ca60 and the TDS is 215~ Currently the MG:Ca ratio is 1.29 - This is my OEBT tank

Ideally I want tank 1 to be gh5 kh1 and Mg:Ca ratio 3.5 - I was thinking to do this is to add pure RO water to lower the tds some more then add more GH until the ratio is where I want it. My question is there a better way to get this ratio and what do i use to raise gh?

Ideally I want tank 2 to be gh 7-8 and kh 3-4 with the Mg:Ca around 3.5. This is the tank that  had the most issues and I lost quite a lot of OEBTs at one stage. I think I have got the WP at a stage where they are surviving and breeding again but I would like to get it a little better for them. I just need some help/instruction to get it there properly. 

I know in both tanks I need to increase the Mg but I dont want the overall Gh to increase or the TDS. I am also not sure the correct product to buy to increase the mg safely. What I have been doing is add RO remineralised with Salty shrimp at a lower tds then what the tank was every water change to slowly bring my tds down. 

Any advise or guidance will be much appreciated. I think Tank 1 would be ok where it is atm but I would really like to get tank 2 closer to ideal if possible.

Thanks.

[JacksonL]

You can't raise Mg without raising the GH and TDS.

best way to add Mg without increasing either too much though would be to just add Epson Salts (MgSO4)

Also what are you using to test Mg and Ca levels? Be aware that most hobby level test kits are horribly inaccurate, and if you are chasing perfect parameters based on their results you could actually be making your water worse.

[jayc]

@Disciple it looks like you have reached a point in time where the use of a premix remineraliser like SS has become a limiting factor.

In order to control GH, you need to dose Ca and Mg separately. But you can't with a premixed product like SS.

If you want to add Mg separately, you'll need to get some MgSO4 from AOS

http://www.aquariumonlinestore.com.au/products-page/chemicals-bulk/magnesium-sulphate-heptahydrate-epsom-salts-1kg/

 

[JacksonL]

You can also just get MgSO4 from most chemist, pharmacies or supermarkets. It depends on how much you need though as the quantities available there are normally <1kg

[jayc]

yes, that's also another possible source.

But be careful not to pick some thing with added scents or essential oils, as many of these products are sold as Epsom Salts or Bath Salts in chemist, or supermarkets.

Your other source of Mg is at a gardening centre (eg Bunnings, Mitre 10).

[Disciple]

Thanks ‌@JacksonL 

I use the API Test kits and I understand that they are not 100% accurate. I think with tank 1 should be fine not making a change as the shrimp are quite happy anyway but I think for tank 2 I would really like to adjust the ratio a little.

Thanks ‌@jayc

Really appreciate the link cause I really didn't want to risk getting the wrong product. I will pop down there on the weekend and buy that exact product.

I believe I have done the calculations right and if I am reading it right I need to increase my Mg to get the ratio "better". Are you able to point me in the right direction for a formula to use or do have any advise as to how many grams I need to add as I do not want to overdose it.

Currently my plan is to continue to lower the gh in both tanks. Tank 1 to about 4 gh and tank 2 to about 7 gh. After that I will check the ratios again, I assume it should stay the same so then I will add the mg the tank to get the ratio back inline. Unless this idea is really bad then I might do a water restart just in tank 2.

[jayc]

If you are only dosing Mg to balance the Ca:Mg ratio then it's trial an error I'm afraid.

There is probably a formula, but I'm no math wiz.

 

Pre-dilute the MgSO4*7H2O into a bottle with some RO water.

Then slowly drip 1mL (per 60L) in at a time and test after each mL added.

 

 

Edited October 7, 2015 by jayc

[Disciple]

If you are only dosing Mg to balance the Ca:Mg ratio then it's trial an error I'm afraid.

There is probably a formula, but I'm no math wiz.

 

Pre-dilute the MgSO4*7H2O into a bottle with some RO water.

Then slowly drip 1mL (per 60L) in at a time and test after each mL added.

 

 

Thanks again Jayc.

I will add a 1ml extra of the diluted MgSO4 with the next water change and I will check how it changes the ratio and then adjust accordingly.

Just to double check I have read it right. I dilute one part MgSO4 to 7 parts RO water?

[jayc]

Just to double check I have read it right. I dilute one part MgSO4 to 7 parts RO water?

No no.

MgSO4*7H2O is just the abbreviation for Magnesium Sulphate Heptahydrate. The heptahydrate part is just 7 H2O molecules that have been added to MgSO4 so it dilutes in water easier.

 

Sorry, I see how it would have cause the confusion.

 

Just dilute 1 table spoon in 100ml of water. I usually store this in an old drink bottle.

I'll use a syringe to make small adjustments to the water parameter using separate bottles of Calcium Sulphate and Magnesium Sulphate.

[jayc]

I will add a 1ml extra of the diluted MgSO4 with the next water change and I will check how it changes the ratio and then adjust accordingly.

Oh, just another word of caution. 

1ml to 60L, so assuming your tank is 60L then the 1ml of MgSO4 is fine. BUT add it slowly over a few hours if possible. The change even though small, can still be stressful to shrimp.

[Disciple]

No no.

MgSO4*7H2O is just the abbreviation for Magnesium Sulphate Heptahydrate. The heptahydrate part is just 7 H2O molecules that have been added to MgSO4 so it dilutes in water easier.

 

Sorry, I see how it would have cause the confusion.

 

Just dilute 1 table spoon in 100ml of water. I usually store this in an old drink bottle.

I'll use a syringe to make small adjustments to the water parameter using separate bottles of Calcium Sulphate and Magnesium Sulphate.

Phew, Glad I asked now.

I was never any good with chemistry. Thanks for clearing it up.

Yeah tank 1 is about 180ltrs and tank 2 is 80ltrs so add a extra 1/2 a ml of Mg in the wc and then see how that changes the ratio's of each tank this weekend. I usually drip the water back in over 2-3 hours when I do my water changes. I might adjust the drip rate to take an extra hour or 2 longer.

Now feel a lot more confident. I think I will also get myself some calcium and potassium incase I need some in the future.

[jayc]

Phew, Glad I asked now.

Now feel a lot more confident. I think I will also get myself some calcium and potassium incase I need some in the future.

No silly questions here on SKF remember.

 

 

[JacksonL]

This should help you work out if your test kits are accurate, as the numbers should all match, as GH is calcium and magnesium:

http://www.lenntech.com/ro/water-hardness.htm

 

if your calcium test is anything other than a titration style kit (salifert etc) I wouldn't be making any changes based on it's results, and I wouldn't trust any of the hobby grade Mg Kits at all.

[Disciple]

This should help you work out if your test kits are accurate, as the numbers should all match, as GH is calcium and magnesium:

http://www.lenntech.com/ro/water-hardness.htm

 

if your calcium test is anything other than a titration style kit (salifert etc) I wouldn't be making any changes based on it's results, and I wouldn't trust any of the hobby grade Mg Kits at all.

Thanks Jackson 

I'll get a salifert test kit on the weekend and test.

[JacksonL]

It is the best as far as hobby level test kits. Only the calcium one works for freshwater though, the magnesium one is saltwater only.

Edited October 7, 2015 by JacksonL

[Disciple]

Only the calcium one works for freshwater. The magnesium one is saltwater only.

That will be fine. I'll just get the Ca one