# Sera Mineral Salt not melting properly in osmotic water



## elettrone (8 Jun 2014)

I'm using "Sera Mineral Salt" to condition my osmotic water to KH 4 but when i add the salts, whatever the concentration it won't melt properly leaving a LOT of white particles in the water solution and thus the KH is never what it is expected to be.
I agitated the tanks for days but the particles just won't melt.
The instructions on the back say that 5g every 100 liters results in a kh of 0.6 so when i dose it in my 15 liters tank i do this math:
dose for 1 liter = 5/100=0.05g and kh 0.6 => KH 4 => 0.05*6.66 = 0.333g => 15 liters at KH 4 => 0.333*15 = *4.995g* and this is the ammount i dose every 15 liters tank.
Am i doing something wrong?
Anyone has experience with this Sera product?
http://www.sera.de/en/products/in_c...aintenance-383/product/sera-mineral-salt.html


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## AverageWhiteBloke (8 Jun 2014)

Sorry no experience with this particular product but I did use a re-mineralising product once before that wouldn't dissolve. Have you tried dissolving it in warm water before adding to the tank. In the end up I just put it straight into the tank dry, at least that way I knew it was in there but it seems odd yours isn't dissolving after time.


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## elettrone (8 Jun 2014)

I will try adding a thermoregulator in the tank plus air bubbles to keep the water in movement. Thanks for the hint.


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## Victor (8 Jun 2014)

You need a low ph to melt it properly. Even this way, it takes 1 or 2 days to dissolve completely.


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## elettrone (9 Jun 2014)

What if i get a stainless steel pot and heat up the osmosis water and the salts on the kitchen fire? It should melt super fast and save me some hassle...?


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## AverageWhiteBloke (9 Jun 2014)

I could be wrong here but if your mineral salts contain carbonates would they not boil off being temporary? Someone more qualified could probably comment. The stuff I used just hung about for 24 hours if I added it on WC day but was always totally dissolved the next day.


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## elettrone (9 Jun 2014)

Well i dunno that much about chemistry but i wasn't gonna boil em up, just heat em enough to melt properly.
Sub 80º Celsius anyway


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## AverageWhiteBloke (9 Jun 2014)

elettrone said:


> Well i dunno that much about chemistry but i wasn't gonna boil em up, just heat em enough to melt properly.
> Sub 80º Celsius anyway


Me neither  When I tried to dissolve the stuff I had in still quite warm, cooled water from the kettle I could stir it until the cows came home and it wouldn't dissolve. I ended up rinsing the container out into the tank just to make sure I got it all.


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## elettrone (9 Jun 2014)

Jesus this is a nightmare....is there no other option to make our own water?


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## AverageWhiteBloke (9 Jun 2014)

Maybe give this a read. Maybe you don't need to put the minerals back in or you might be wasting time and money using RO in the first place. Ultimately though if you put the specified amount directly into the tank at least you know have added it. With such a small volume of water you are dealing with I wouldn't get too hung up on the test kit and what it's saying.


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## AverageWhiteBloke (9 Jun 2014)

This might also be of some use.


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## elettrone (9 Jun 2014)

I need kh 4 to get ph 6.6 with CO2 so yes i need RO.
Anyway i'll give those link a  read.


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## AverageWhiteBloke (10 Jun 2014)

Out of curiosity how come you need 4kh water with that PH, do you have some sensitive fish?

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## elettrone (10 Jun 2014)

Otocinclus Affinis and Corydoras panda live in nature with a 6-6.5 ph so i try to get as close as possible.


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## AverageWhiteBloke (10 Jun 2014)

Ok I get you, I keep the exact same species myself. Luckily I have V soft water coming out of my tap but because of the stone I have in my tank my KH naturally rises throughout the week. I think in the case of the fish you have there they're not too sensitive to water hardness, perhaps the ottos but I would say unless you are trying to breed stability and low pollution would be more of a concern than the actual hardness.

What's coming out of your tap, do you know? could you possibly dilute down your existing tapwater with RO to try and reach your target. Maybe you could use pure RO and add something to the tank itself, I read in one of the posts I linked something about maybe adding a little piece of cuttlefish. Maybe a few shells of some kind.

You have quite a small volume of water in the tank so stability will be the hardest part. I have seryu stone (apologies for not knowing how to spell it ) Could you incorporate a couple of small stones somewhere in your scape. I find having these things in softwater release a small amount in the tank gradually which is a bit better than dumping a load of salt in there in one go.

You also need to bear in mind that most fish are captive bred and although replicating their natural environment is a good thing in the case of hardness they are quite flexible at adapting as long as it's gradula. It's more a long term effect issue and what keeping them in water they haven't evolved to live in may have over the long term. I have read of Discus being kept quite happily in liquid concrete  only softening the water down for breeding purposes. The TDS is probably a better gauge of hardness than your KH/GH measurements anyway way. In my case in my main tank dosing EI my GH 4 and KH 3 which you would assume to be of very low hardness but the TDS measures the day before a water change at 250ppm which is moderately hard water. That's what the fish will feel if you like. Luckily I have tapwater coming out at 40ppm so it's just a case of doing some extra water changes to reduce this down when I feel it's getting too high.

Not sure whether the build up of TDS is through the salts I dose, pollution levels or both but either way it's best kept down for softwater fish. From what I understand living in extreme hardness conditions which they are not used to has a detrimental effect on kidneys of the fish which regulate the salt content of the fish to keep it in balance with the surrounding water. Small deviations between 1 and 2 degrees as long as gradual shouldn't be an issue unless they were dumped straight from one to the other which is why fish need acclimatised when going in new tank.

PH is a different thing, from what I understand PH affects the blood of the fish transporting oxygen around the system so big swings can do serious damage. Adding KH in a lump can cause a quick PH swing hence it's probably better practice to either have something in the tank that does this gradually or to add a small amount of your Sera stuff daily which might help in it dissolving. Someone mentioned earlier that you need acid water to dissolve it, that may be the case with the acid reacting with the carbonate to break it down so dumping it all in maybe won't help.


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## dw1305 (10 Jun 2014)

Hi all, 





AverageWhiteBloke said:


> I could be wrong here but if your mineral salts contain carbonates would they not boil off being temporary? Someone more qualified could probably comment.


No, they would just come out of solution as the temperature rose, and re-dissolve as it cooled.





elettrone said:


> Well i dunno that much about chemistry but i wasn't gonna boil em up, just heat em enough to melt properly. Sub 80º Celsius anyway


 Carbonates are strange because they are more soluble at lower temperatures. 

This is because their solubility is dependent on the CO2 ~ HCO3-  equilibrium.

*My suspicion would be that if you mixed the SERA salts with sparkling (added CO2) mineral water direct from the fridge they will go into solution straight away.*

Because all gases are less soluble at higher temperatures, as you get towards the boiling point of water the levels of dissolved gas become very low and carbonates are deposited, dependent upon their solubility. Because CaCO3 is less soluble than MgCO3 (and a lot less soluble than K2CO3 or Na2CO3) it precipitates out first.

cheers Darrel


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## AverageWhiteBloke (10 Jun 2014)

> Someone more qualified could probably comment.


And then they did  I gave it my best stab though.


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## dw1305 (10 Jun 2014)

Hi all,





AverageWhiteBloke said:


> I gave it my best stab though.


 And it would be right 99% of the time. Heating is what you do to get nearly all salts to go into solution, carbonates are an exception. 

Hopefully the OP can try some cold sparkling mineral water and they will dissolve.

cheers Darrel


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## AverageWhiteBloke (10 Jun 2014)

> Hopefully the OP can try some cold sparkling mineral water and they will dissolve.


Excellent, I learn something new every time I pop in here. I'll try that myself just out of curiosity with the stuff I have. As I said I don't really add anything any more to increase hardness due to the above but I don't suppose it would do any harm when I'm doing bi-weekly 50% changes usually a couple about every every other month to raise the KH a little. I have next to zero coming out the tap so although the bi-weekly reduces tds overall it probably has it's most dramatic effect on KH levels. I also add Mag sulf at water change.


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## elettrone (14 Jun 2014)

In the end i got tired of this salts complication and went back mixing tap water+bio and osmosis water, thanks anyway.


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