Very Cloudy Water... Weird Salt Reaction?

[kpris]

So i finally got around to starting my first marine tank and have been doing extensive research for months about it. So naturally the one area i didn't even think to research on causes me trouble =(

Basically i picked up some salt mix (instant ocean) yesterday, had some previously made up de-chlorinated water (tap water, water stats are pretty good in my area) and mixed the salt into the water. The result was a very cloudy mixture =/

Now the lady at the the LFS did warn me that there would be some cloudiness and it should pass in a day so i waited overnight and checked again in the morning and it's still damn cloudy. So i hopped onto google and tried to find out some info. Apparently alot of other people have had this issue, some of them say it passed and was fine after, others say they chucked it all out and started again, others say it some kind of calcium precipitation? So i should increase water flow, so i'm now just waiting with a massive powerhead (and two smaller ones) chugging water around and hoping whatever it is dissolves properly.

So what do you guys think? What exactly is it? Have you had this problem before?

Also yes I'm sure it's not the sand. My annoying brother chucked it in without my consent *glares*

and a picture is attached... taken with a phone camera so please excuse the quality

 

[SkiFletch]

It is a precipitate, tons of granules of tiny calcium carbonate salt. It's kinda funny, I just discussed with another member about how using tapwater and seawater mixes so I'll just copy and paste it here . One question, you did follow the directions on the salt mix in terms of number of cups of mix per gallon right? What does your salinity measuring device tell you about how much salt you've got in there?


"Seawater mixes contain primarily sodium, chloride, magnesium, calcium, and carbonate. When mixed to a salt concentration of 35ppt/1.026sg with pure water (ie RO or distilled) the resulting solution is nearly saturated in therms of the later three which means you can't dissolve many more ions into the solution before they start forming back into salts. Now, most tapwater contains magnesium, calcium, and carbomate in it. Thus when you add enough seawater mix to get a salt concentration of 35ppt/1.026sg with tapwater you now have MORE mag/calc/alk in solution. Depending on how much your tapwater has, you can supersaturate the solution which means you have too many of the ions in solution and they want to go back into salt form. They do so by forming calcium carbonate salt which is either a white chalky powder or in high enough concentrations is like thick chalk called a precipitate. The precipitate is more likely to form if the pH is high, the temperature is low, or the water is stagnant. Conversely, lowering the pH, raising the temperature, or stirring up the water will act to raise the saturation point and deter the formation of calcium carbonate precipitate.

So, oftem times (but not always) when tapwater is mixed with seawater mix in a bucket with nothing else, the resulting solution is cold, has a high pH from excess carbonate, and is stagnant. This often creates conditions ideal for the formation of calcium carbonate precipitate in the bucket, lining it with a hard white residue. Adding a powerhead to move the water will increase gas exchange (thus increasing CO2 exchange) and keep the pH a tad lower. Furthermore it adds energy to the bucket in the form of moving water which deters the formation of calcium carbonate. And finally, adding a heater allows more solutiblity of carbonate and prevents precipitation."


So yes, heat and water movement will help. You can also get a foam filter on the inlet to one of your powerheads to help out. If after a couple days the water remains cloudy, add an ounce of vinegar. Normally I never reccomend this method when there is livestock in the tank cause the vinegar can cause a major pH crash, but since you've just got water and salt and nothing live in there, you can go ahead and try it.

 

[kpris]

Yes it said 1cup per 2 US gallons... I'm fairly sure I've calculated that right.
pH is around 8.4 and strangely calcium is quite low at 300ppm, salinity is also slightly low 1.018. I didn't know whether or not i should add more salt mix or wait a bit...
The water i added the salt to did have a little power head but was pretty cold and my tap water comes out at around 8.1 pH so i suppose conditions weren't that great XP
Also thanks for that it skiFletch =) Very informative!

 

[SkiFletch]

Yup, that sounds about right. Have you tested your tapwater for calcium and carbonate? Likely it's high in carbonate The situation you're describing here makes perfect sense, the calcium is used up in the precipitation of calcium carbonate thus free calcium is low in the water colum and the high pH makes for ideal formation of of the precipitate. Often with enough time/air enough CO2 is introduced to the system to reverse the precipitation reaction and clear the water. Good luck and keep yus posted

 

[kpris]

XD You're exactly right! it is pretty high in carbonate. I guess i need to develop a method to get rid of that.
I'm trying to cheat and think back to high school chemistry to see if i can actually produce carbon dioxide to make it quicker... Nothing safe is coming to mind XP
Maybe i should pick up a C02 diffuser...

 

[kpris]

Just another question...
Is calcium carbonate bad for bacteria?
As in would it be bad to add crushed coral substrate and live rock even if it's not fully cleared yet? Just because I've agreed to buy live rock off someone who's shutting down their tank and would like to do it quick. They were willing to hold it for me for a week or two (it's almost the end of that first week) but I'm not sure how much longer.

 

[SkiFletch]

No, Calcium Carbonate does not harm anything. Other than looking nasty, the only problem with calcium carbonate is that the cloudiness isn't good for photosynthetic organisms since they cloudiness blocks light . Actually, getting LR in the tank with bacteria and other processes that will naturally lower the pH, generate CO2, and use excess carbonate will only help you out.

Oh and the only way to economically remove carbonate from tapwater is through RO filtration

 

[kpris]

Just a quick update... water doesn't appear to be any clearer but it's only be a day so that's fine but I'm officially confused.

Thinking back to highschool chemistry (and my soft drinks in the fridge), CO2 dissolves better in cold water, and according to alot of scientific sites i've been googling calcium carbonate also dissolves better in cold water which is why calcium concentrations tend to be higher in deep ocean. Yet heating raises the saturation point but the molecules won't want to let go of each other (dissolve) ... o_o

So... it's kind of an equilibrium thing? Where i have to get the balance right except that CO2 is always being constantly introduced which would be slower if the temp is high...

So... what's the ideal temperature here?? I've got it set to 23 degrees Celsius atm.

 

[SkiFletch]

Yes, it is exactly an equillibrium thing. You are correct about the dissolution rates of CO2 and CaCO3 and their relation to temperature. However, you have to remember magnitudes of dissolution as well as trends. The magnitude of CaCO3's dissolution rate in water is VERY LOW especially at higher pH's. It's like you're trying to change the dissolution rate of something that's almost un-dissolvable. It's almost like pouring a cup of hot water into a lake. Sure you're raising the temperature, but not in a significant manner.

A similar case goes with CO2. It is actually pretty easy to dissolve CO2 in water, especially when surface tension is broken via movement. As such, a minor rise in temperature only barely affects it's dissolution rate.

However, an Acid introduced into the solution will cause a dissolution reaction of CaCO3. Furthermore, adding heat to this acid-aided equillibrium reaction significantly affects the dissolution of CaCO3. So while the increased temp may slightly hinder the addition of CO2, or the natural dissolution of CaCO3, the limiting step (the acid reaction) is aided by heat.

The reason CO2 is a good acid to use in systems with livestock is that it does not create complex cabon byproducts like Acetic Acid (Vinegar) does when it breaks down). When acetic acid breaks down in the dissolution of CaCO3, it creats carbon compounds that fuel algae growth and respiration. That in turn will create more CO2 and deplete O2, thus possibly suffocating and killing livestock, especially simple invertebrates, which then create waste products like ammonia which kill more things and the tank can crash really really fast (but the water will be clear...). And I believe there are also some articles by Randy Holmes-Farley about correcting cloudy water like this and he goes into the actual chemical processes involved.

If you poke around the corners of the net you may find stories of people using vinegar to correct calcium carbonate precipitate and having major tank crashes. A local reefkeeper in my own club did this and barely saved his system by adding a lot of airstones, dripping kalkwasser, and jacking his surface agitation through the roof. All his fish were gasping on the sandbed for O2 and barely survived. He was lucky he knew what to do though...

Anyway, I know that's a lot and I hope I haven't bored you, but hey, you seem interested

 

[kpris]

Ohhh i see. Thanks for that, makes alot more sense now.

And no it wasn't too long at all. I rather like long detailed explanations, I'm a bit of a perfectionist/control-freak so i like to know exactly what's going on

 

[seffieuk]

Hi

It happened to me as well....................don't panic it will come right in a couple of days as Ski says

Seffie x