Does new sand and ceramic rock cause alkalinity and calcium to drop?

[Recci]

I set up a new red sea max nano 3 weeks ago. I had a 35L nano up and running for over a year before that with lots of live rock and just a hob filter and no skimmer. I made 75 litre of new salt water with coral pro salt to the recommended 34ppt. I measured the alk and calc which seemed roughly inline with what it was supposed to be with that salt. 450 ca KH around 11 dkh. I then used a new sand with only a small amount of sand from the old tank and I moved over all the mature live rock from the old tank and added a load of new ceramic rock. The live rocks had a few mushrooms and other small sofites on it and 1 small duncan plus one small candy cane. I moved over all the CUC and the two fish i have a small azure damsel and green chromis. I figured that since i am not increasing bio-load and the rock is mature and was move from tank right into the other within seconds that there wont be a cycle. The live rock will seed the new sand and ceramic rock.

So far everything has went to plan and the corals and fish are looking better than ever except for my Astrea Snails which now seem to be falling over and getting stuck which they never really done before. I am keeping a close eye on the params and have noticed that my alk and calc have dropped much faster than I expected.

The alk dropped from 10/11 to 6dkh in 7 days and thats with a 10% water change. The calc was down to about 400/410. Does this seem normal such a small tank with no sps and only two small lps and no visible coraline algae growing yet? Does the calc drop and alk number seem right? I was expecting it to take a few weeks to see much of a drop in anything.

Its taking 8 mil of red sea reef foundation A and 9ml of foundation b to keep ca and kh stable at around 450 and 11 dkh. Mag is stable.

I was told in another foum that it could be the ceramic rock thats causing this and I red on the red sea website that a new sand bed can also cause this.

What do you guys think?

 

[bertoni]

New sand and rock might provide nucleation sites for precipitation, so, yes, they might cause a drop in calcium and alkalinity. That drop is significant, though. I'd probably dose the level back up to 7 dKH or so, and start doing regular checks, maybe every day for a few days. There's no coralline showing at all?

 

[mcgyvr]

Yep.. keep testing.. may have just been a fluke..

 

[Recci]

Its not a fluke the tank has been consistently dropping 1.5dhk a day for 3 weeks. I dosed it back up to 11dhk where I want it to be.

 

[bertoni]

I'm not sure whether you're seeing precipitation on the sand and rock surfaces, or maybe there's coral or coralline growth to blame. 1.5 dKH per day is a lot of consumption, but my soft coral tanks went through 2-3 dKH per day for years due to coralline growth. Do you see any buildup on heaters or inside pumps?

 

[Recci]

No there is no sign of coralline algae yet and the coral are not consuming that much. There is hair algae and slim though. According to someone on another forum the ceramic rock is absorbing the alk and on the red sea website it says that a new sand bed can cause this. I am assuming I am getting a double whammy effect.

 

[Dan_P]

New sand and rock might provide nucleation sites for precipitation, so, yes, they might cause a drop in calcium and alkalinity

Randy said the same thing about aragonite sand in 2002. Great memory Jonathan!!!

 

[bertoni]

I agree that the sand and the rock are the most likely sinks, then. It should pass, but let us know if it keeps up for more than a week or two.

 

[Recci]

Just an update to this issue. I am 3 months in and it is still dropping large amounts of KH. I added a dosing pump about 6 weeks ago and have been dosing around 12ml a day (spread out over 8 doses) of red sea foundation B liquid and i still cant get the alk to stabilise. The drop is slower but not stopping. Calcium is more or less stable and mag hardly moves. The only corals i have added is hammer, torch and 4 smallish monti frags.

 

[Recci]

I am doing into the display tank as i have no sump. But its dosing so much that the filter sponges in the back compartment are starting stiffen up.

 

[bertoni]

That's not all that big a dose, I think, but I am wondering about the sponges. You might try dosing some baking soda for a while, as the lower pH can cut precipitation.