Soluability in hot water (chemistry question)

[daveedka]

Hi Folks,
I'm trying to switch over from Baking soda to Calcium carbonate for my change water. My reasoning is that with my soft water, I worry about the snails getting enough calcium. And since I'm adding KH to my change water to match the tank, I'd like to use the caCo3 instead. But alas it doesn't dissolve at a rate acceptable to my change water preparation so here is my question. Will it dissolve faster in boiling water. My thought is to dissolve it in a small quantity of boiling water and then add it to my prep tank to mix after dissolution. I have ordered some very fine Calcium carbonate from Gregg Watson (thanks for the link Len) and thought I'd try it to see if it was faster. any thought would be appreciated. My snails currently have cuttlebone to chew on, but I would like to just get the water to a point where it provides for their needs.
dave

 

[ChicoRaton]

it will dissolve more quickly in hot water, but use plenty of hot water. If you dissolve it in a very small amout of water and add it to your prep tank, then the caco3 may precipitate out again. hth.

 

[JSchmidt]

Carib Sea makes a product called AragaMilk that is essentially a slurry of calcium carbonate. You can add it directly to the change water, and whatever doesn't dissolve immediately will do so as KH drops and pH with it. It will take pH up a bit, but so will baking soda, so if baking soda is working for you, AragaMilk probably will, too. It likely is very similar to the preparation you're getting, but it's very easy to dose and add with water changes. (It makes the water a bit milky, but only for several hours.)

Another option would be to put some aragonite sand in a filter bag and let it slowly dissolve; this would in effect automatically replace calcium carbonate on a continuous basis. Probably not the best solution if you routinely do large-scale water changes, but if you do smaller changes (30% or less at a crack) it should be fine.


HTH,
Jim

 

[HazyWater]

A better question is why worry about it dissolving? Sprinkle some in and it will eventually reach an equilibrium in the tank. If it doesn't all dissolve, so what? Snails are mighty resourceful and as they use calcium carbonate, more will dissolve into the aquarium, maintaining that equilibrium. You can put some shells in there too or aragonite as JSchmidt posted. They will achieve the same effect.

 

[OrionGirl]

I have a similar problem with my tank at work--won't use tap water, but the drinking water is RO filtered, so use that instead. Of course, this results in really low KH, and pH. Instead of worrying about modifying the water, I added a few empty snail shells to the tank. Brings the KH up to 4, and the pH stays stable at 6.8. I do fairly large water changes--2 gallon on a 5 gallon tank--and the parameters are at normal within 6 hours. I only have cherry barbs, a few pond snails and some plants in the tank--but the crypt in there hasn't melted in a long time. It used to melt on me about every 6 months (which was why I started monitoring the tank!). I watch the shells though--and when one starts getting large holes in it, I add another one.

 

[daveedka]

A better question is why worry about it dissolving? Sprinkle some in and it will eventually reach an equilibrium in the tank. If it doesn't all dissolve, so what? Snails are mighty resourceful and as they use calcium carbonate, more will dissolve into the aquarium, maintaining that equilibrium. You can put some shells in there too or aragonite as JSchmidt posted. They will achieve the same effect.

The concern is with raising the KH and Ph of my change water not with keeping the tank from dropping. If I added it to the tank, I'd have to have a tank KH of about 5 and then do changes with a kh of 2-3 and things would be bouncing around more than I like. I am a bit neurotic about stability I will admit, but with low KH from the tap I really prefer to make the adjustments before it goes in. The tanks don't ever show a change unless my water changes cause it. I just figured if I was changing Tap water I might as well do it in a way that benefits my snails as well. I may check out the AragaMilk, as that sounds like a good idea if it isn't too expensive. Right now I have 5 #'s of crushed coral in my prep barrels, and water circulates through it all week and never raises the KH. It just doesn't have time to dissolve enough to help so I end up adding baking soda before I do my weekly partials.
dave

 

[happychem]

CaCO3 is a funny compound, it's less soluble in hot water than in cold. This is why you get that white buildup in your tea kettle. So go with very cold water instead of hot and you'll find it dissolves much better.

On a side note, if you mix it the day before your water change, that should solve the problem anyway.

Also, remember that CO3-- has twice the effect on KH as HCO3-, so use half as much as you normally would.

 

[mogurnda]

I also have soft water and am doing something like Jim suggests for my tanganyikans. Instead of aragamilk, though, I use "kalkwasser," calcium hydroxide (aka pickling lime). It's used in marine aquaria to boost calcium, and is quite cheap. My mix is 6 tsp kalk powder plus 100 ml vinegar (brings pH down a bit and helps provide carbonate) in 2 gallons of water. Just add it slowly to prevent pH swings.

Aragonite sand is certainly a possibility.

 

[JSchmidt]

I also have soft water and am doing something like Jim suggests for my tanganyikans. Instead of aragamilk, though, I use "kalkwasser," calcium hydroxide (aka pickling lime). It's used in marine aquaria to boost calcium, and is quite cheap. My mix is 6 tsp kalk powder plus 100 ml vinegar (brings pH down a bit and helps provide carbonate) in 2 gallons of water. Just add it slowly to prevent pH swings.

Aragonite sand is certainly a possibility.

Dave, do you buy yours thru aquarium suppliers, or is there a generic form of calcium hydroxide you buy locally? I like Aragamilk, but I'm always on the lookout for something cheaper for my many Rift Lake cichlid tanks.

Thanks,
Jim

 

[mogurnda]

I have a small tank (up to now), so I've been buying the stuff from aquarium suppliers. Reefers with real tanks save money by buying Mrs Wages pickling lime.