Cloudy Water

[hattrick58]

I've had this happen before, but not while there were corals in the tank. Did an 18 gal water change Sat. Sunday, the water was cloudy (milky) and the polyps (I think there polyps?) were closed. The fish don't seem stressed and are acting normally. Today is the same thing. I put new carbon in this morning. Water parameters are: Ammonia, trites, trates - 0 (yes, trates are reading 0!), pH - 8.2, SG - 1.023, alkalinity - 6 meq/ltr, calcium - 400 mg/ltr, temp - 81. I think the fish will be okay, it's the corals I'm worried about. I'm guessing a bacteria bloom, but why right after I did a water change? I did add Reef Calcium and Reef Complete (Seachem) Sat. after the water change. I'd appreciate any input.

 

[cboyfan2020]

did the water mix up the sand when you were dumping it back in?

 

[hattrick58]

Yes, but the water was clear Saturday after the water change. I first noticed it Sunday A.M .

 

[mousers68]

Did you add the two chemicals together or did you wait before adding the two?
The kit I have says the levels should be KH 180-300 Also if the "water hardness is over 150 ppm then there can be formation of white mineral deposits on aquariums and equipment"
I notice when I added those they turned milky.
May want to check that out further IMO

 

[hattrick58]

I added them within 5 minutes of each other. Thanks for the tip, next time I'll wait before adding them. This morning the water looked clear, just waiting to see of the corals will open.

 

[broomer5]

hattrick58
As I see it ( others may disagree or contribute the cloudy tankwater to another cause )
More than likely, the tankwater is supersaturated with carbonate( part of the alkalinity ) and you've experienced some CaCO3 calcium carbonate fallout .. or precipitation.
The water appears cloudy.
The tankwater is supersaturated with carbonates IN RELATION to your calcium level of 400meq'L ..... at your pH of 8.2
Was your alkalinity readings of 6.0 meq/L ( 16.80 dKH ) before or after you performed the water change ?
Same with your calcium reading of 400 ... was this prior to or after the water change ?
At a pH of 8.2 ...... I think your alkalinity of 6.0 meq/L is too high for the amount of calcium you have. I would consider backing off on the buffers and reef alk builders for awhile. Some might suggest adding calcium chloride to bring your calcium level up to a "balanced" level with your alk.
As the pH rises .... some of the bicarbonate in the tankwater can be changed over to carbonate. Based upon where your calcium levels are at ... when this happens ... calcium carbonate can form in the tankwater as a solid, and precipitate out of solution.
This can easily cause the tankwater to become cloudy.
If the newly mixed saltwater does not have the same levels of pH, alkalinity and calcium .... compared to the tankwater ....... then doing an 18 gallon water change on an 80 gallon tank ( say 70 gallons of actual saltwater ) that's around a 25% water change.
Again, if the new saltwater is not the same as the tankwater - it can cause some problems.
Tankwater chemistry is always changing as CO2 gas enters/exits the equation. CO2 gas enters & exists the tankwater at the tankwater surface interface, and CO2 gas levels fluctuate as a result of fish respiration and alage photosynthesis during a 24 hour period.
The pH will normally swing from day to night .... and the total alkalinity ( bicarbonates to carbonates ratio) will adjust their levels accordingly. It's all part of the natural chemistry that occurs in our tanks all the time. Nothing we can do about it besides trying to understand it. For most of us ... it's not real easy to understand either. It can be tricky - but it does follow some rules. The rules can be understood - and the outcome is somewhat predictable.
Our alkalinity test kits ( most of them ) measure total alkalinity. Many of our kits do not distingusih between the actual bicarbonate and carbonate amounts. The kit just tells us "total" alkalinity.
But in reality ..... most of the total alkalinity is a result of the bicarbonate. It's the most abundant "buffer" in the tankwater.
Carbonate contributes to the total alk as well .. but is not near as concentrated as the bicarbonate.
When pH changes, or we disrupt the balance of these compounds in the tank by doing "something" ( like a water change ) it's very possible for bicarbonate to shift over to carbonate.
If the pH, total alkalinity and calcium levels are "balanced" .... then we don't normally see this calcium carbonate precipitation.
If you run your calcium too high in relation to the alkalinity ... precipitation can and will occur.
If you run your alkalinity too high in relation to the calcium level ... precipitation can occur.
As the pH changes ...... it can "force" the CaCO3 calcium carbonate precipitation to occur ........ until the chemical reaction comes to a halt naturally.
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I'm guessing that something like this happend with your tankwater chemistry last weekend.
Keeping all the levels in the tankwater is often times difficult .. until you find an approach that works for your individual tank.
Knowing what is "balanced" and "unbalanced" is the first step in figuring out the levels that "your" tank should be maintained.
Here's a handy chart that I use often.
This chart shows various total alkalinity levels and calcium levels that many would consider to be "balanced" ..... at the given pH value of 8.2
I like to maintain my tanks at a pH of 8.2
Kalkwasser is ideal for helping to keep the pH up - as it tends to want to drop over time. It also adds OH- hydroxyl ions ( which can help to maintain bicarbonate levels as well, in addition to maintaining Ca+ calcium ions ).
Keeping the pH at 8.2 ....... I like to shoot for an total alk level between 3.00 and 4.00 meq/L ( 8.4 to 11.2 dKH )
At these levels - it's pretty easy to keep the calcium levels between 420 and 440 accordingly.
One last note: Did you allow the newly mixed saltwater to aerate overnight with a powerhead/heater ?? - or did use it for the water change shortly after you mixed it up ?

 

[hattrick58]

Thanks for all the information. I knew that pH, calcium and alkalinity were all related and can cause problems if one goes out of wack, but not to the extent of which you speak! The water parameters were taken about 2 hours after the water change. The salt water was mixed friday evening and allowed to aerate for 14 hours. It was also heated to tank temp (81 degrees) prior to adding it to the tank saturday afternoon.

 

[broomer5]

You may want to run this past Bang Guy or some others on here too. There are some sharp folks on here regarding this concern.
See ya