How do I stop calcium carbonate precipitation?

RandoReefer · Dec 17, 2014

I have calcium carbonate precipitating on my back walls of my glass, walls of my sump, and heaters. It's not very thick, but difficult to scrape. How do I rid myself from this eyesore and still maintain my current levels?

ImageUploadedByTapatalk1418863098.421326.jpg

ImageUploadedByTapatalk1418863110.171486.jpg

ImageUploadedByTapatalk1418863119.805698.jpg

I have approximately 125gal total water volume within my system (DT, sump, fuge).

I daily dose 50.6mL of Alk (baked baking soda solution) as well as 50.6mL calcium chloride solution.

I have a 30gal ATO reservoir with limewater (saturated with 2tsp/gal ratio)

My pH swings from 7.78-7.98 throughout the day (Apex pH probe recently re-calibrated)

Temp stays controlled at 77.8-78.0

(Red Sea Pro test kits.)
KH- 9.2dKH
Ca- 440
Mag- 1400~1440

Salinity- 1.025

Nitrate- 0 (Salifert)
Phosphate- 0.0 (Hanna)

Thanks in advance!

fishmommy · Dec 17, 2014

Are you sure about the mag level? When I had precip. It was low mag.

RandoReefer · Dec 17, 2014

fishmommy said:
Are you sure about the mag level? When I had precip. It was low mag.

I test all three about 2-3times per week with Red Sea kits. Results are fairly consistent.

fishmommy · Dec 17, 2014

Are you dosing alk and cal at the same time?

RandoReefer · Dec 17, 2014

fishmommy said:
Are you dosing alk and cal at the same time?

No, I have them offset by 30min. But that's a valid possibility. I currently dose 2.2mL hourly for 23hrs each, offset by 30min. (Calcium dosing is at the top of the hour for 2min, Alk is at the half of each hour for 2min)

I may have to shorten the dosing and separate the two by night and day.

fishmommy · Dec 17, 2014

You could try that. I have reached the end of my ideas so good luck and hopefully someone with more knowledge will stop by and comment

RandoReefer · Dec 17, 2014

fishmommy said:
You could try that. I have reached the end of my ideas so good luck and hopefully someone with more knowledge will stop by and comment

Your input is much appreciated! Always great to have the thoughts of a whole community at our fingertips. Thanks!

Randy Holmes-Farley · Dec 17, 2014

It sounds like everything you are doing is appropriate.

Where is the limewater added in relation to the precipitate?

The wall of my sump near my limewater drip tip does get coated.

RandoReefer · Dec 17, 2014

Randy Holmes-Farley said:
It sounds like everything you are doing is appropriate.

Where is the limewater added in relation to the precipitate?

The wall of my sump near my limewater drip tip does get coated.

Currently, the ATO limewater is pumped into the corner overflow. The first picture is of the remote refugium. Previously I had the limewater pumping straight into the refugium, but that "thicker" precipitate was quickly building on the glass, so I moved it.

The precipitate is now a very light coating on the back glass of both tanks. I just reprogrammed the dosing pumps to dose only 9hrs each at 5.5mL per hour. This allowed me to put more separation between the Ca and Alk dosing. (Alk- 22:00-07:00, Ca- 09:00-18:00)

Hopefully this helps! [emoji16]

Randy Holmes-Farley · Dec 19, 2014

I'm not sure why you are getting that,.

Is there a low of flow where you add the limewater?

How fast is it added?

RandoReefer · Dec 19, 2014

Thanks Randy,

There's plenty of flow where the ATO pumps into. It goes straight into the top of a corner overflow. I have a MagDrive12 return pump and two of these corner overflows and PLENTY of flow.

The ambient room temp is 69Â° and the tank is 78Â°. My 30gal, trash can, ATO reservoir takes approximately two weeks to empty using a Tunze Osmolator 3155.

I need to scrape this precipitate off and see if it returns with my new dosing schedule. I'll update with my findings.

Randy Holmes-Farley · Dec 20, 2014

OK, sounds good.

Good luck.

Reef_in_Denver · Jan 13, 2015

Any updates here as I am dealing with a similar issue?

RandoReefer · Jan 13, 2015

Reef_in_Denver said:
Any updates here as I am dealing with a similar issue?

Sure thing! The problem seems to be resolved by adding more of a gap between my dosing. As stated above, I was dosing Ca at the top of the hour and Alk on the half of every hour. Since then, no precipitate on the back glass.

One issue I'm running into now is my skimmer going crazy in the middle of the night. So much so that I've had to add a float switch inside my skimmer cup that will shut the skimmer off after it fills. I'm assuming it's being caused by the Alk...? I'm not sure if anyone has reported to you, Randy Holmes-Farley , whether recipe #1 for Alk caused their skimmer to over produce and runneth over?

Randy Holmes-Farley · Jan 13, 2015

Alkalinity additives do not usually impact skimmers. What exactly are you dosing?

RandoReefer · Jan 13, 2015

Thanks Randy,

I dose BRS Calcium Chloride during the day (no visual impact on skimmer). A solution of 2-1/4 cups of baked baking soda to 1gal RODI water, during the night 20:00-05:00. And Kalkwasser through my ATO.

When I wake, the skimmer cup is either full or overflowing. Once I drain the cup and adjust the skimmer gate valve, the skimmer returns to normal (how it should be expected to run). This was happening with my old skimmer as well, which I upgraded after Christmas.