Reefs.org Forums

[crackerbuzz]

Hey, just wondering. I am using Medicinal grade Calcium Chloride and my Acropora are loving it.

However I hear that Chlorides can build up in the system.

Can someone elaborate on this for me.

Regards
Craig

[Guy]

If you do regular water changes then there's really no problem. What's the Carbonate source you're dosing with the Calcium? If it's Sodium Carbonate or Sodium Bicarbonate then the Chlorides will form Sodium Chloride. Over time without water changes this will make the Sodium Chloride concentration different from Natural Sea Water. I don't know if that's OK but it's probably fine, just different. Regular water changes will restore a more natural balance.

[crackerbuzz]

Yes, I am doing 30% water changes once every 5-6 weeks.
(I'm running 365 Gallons)

I am dosing Sodium Bicarbonate, (Food grade).

So what happens in an aquarium if chlorides build up?

Any Ideas?

Thanks again
craig

[Guy]

Nothing that I know of.

[Rinaldo Fontenele]

Our friend Guy is correct, if you do changes of water, the concentration of cloride stay low.

[yslexdia]

Hey, just wondering. I am using Medicinal grade Calcium Chloride and my Acropora are loving it.

However I hear that Chlorides can build up in the system.

Can someone elaborate on this for me.

Regards
Craig

I don't think there is any real cause for concern. Chlorine ions represent a large component of seawater, making a shift in chlorine ion concentrations difficult to acheive...especially when dosing calcium, a relatively minor component of seawater. If you were talking about adding buffers we'd be talking about big difference in magnitude as far as the actual additions and possible effects are concerned. But because chlorine is so relatively abundant, I don't think you'll see a significant shift in ion balance.

Here's an interesting bit about chemical dosing and ion ratios:

Sodium hydroxid (NaOH), sodiumb bicarbonate (NaHCO3) or sodium carbonate (Na2CO3) can be used to adjust the alkalinity and pH. Powedered limestone [calcite or calcium carbonate (CaCO3)] is not recommended because with time, the calcium in the lime may change the ratio of major cations (Breder and Smith 1932). Cooper (1932) reported that at the Plymouth Aquarium in England the addition of lime to maintain pH eventually increased the calcium concentration in the water to 0.62 g/l compared with 0.39 g/l in the seawater directly offshore.
Sodium, the predominate cation in seawater, can be added as carbonate or bicarbonate salts for longer periods before the cation balance is upset. Breder and Smith (1932) estimated that if all thebicarbonate ion in seawater at the New York Auarium were to be replaced over a period of 2.5 years with sodium bicarbonate, the sodium level would increase a mere 0.5%. If lime were used instead, the calcium level would increase by 10%, or 20 times the molar concentration of calcium in offshore seawater.

^^from Seawater Aquariums: The Captive Environment by Stephen Spotte.