Calcium build up

[user48953]

Sorry, but I'm not sure if this is the correct forum for this type of question, or not..

Recently i've noticed there's a calcium buildup on the ceramic parts in my pumps (more on some pumps then others).. i drip kalk as top off water and just started using Randy's 2part recipe #2 :thumbsup: for about 2.5 weeks now too, and not to mention the weather has gotten a little warmer.. what exactly is causing the calcium to harden on the ceramic shafts and parts?? is it the kalk, 2part, or all the above?

i've read some posts that say that if you dose (kalk, 2part, etc.) then you will have to clean your pumps almost monthly while people who run calcium reactors are more like 3-4 months.. does the alk/Ca from dosing react differently from alk/Ca from a calcium reactor? and does heat factor in as well?

[Randy Holmes-Farley]

This is the place for reef chemistry questions, and this is one. :)

Calcium carbonate can precipitate in a variety of places, and on warm pump parts and heaters is especially likely as CaCO3 is less soluble in seawater at higher temperature.

All reef aquaria are supersaturated with respect to calcium carbonate, so some slow precipitation is very common.

When calcium, alkallinity, and especially pH get too high, the precipitation is accelerated. Low magnesium also accelerates it. Folks with CaCO3/CO2 reactors do not usually have such problems as much because they run at a lower pH, although this is not a net benefit, IMO, as the low pH is also making it harder for corals to calcify.

Do you know how high the pH is getting?

If you used less limewater and more DIY recipe #2, the pH will not get as high.

[user48953]

Randy.. Hope you had a good and safe 4th! and thanks for clarifying this..

I didn't know that CaCO3 was less soluble at higher temperature.. when the temperature gets warmer, does it just precipitate in the water column? then stick onto anything warm/hot?.. i guess what i'm asking is, how does it know to harden onto heater/pumps instead of a snail's shell? :)

i think my pH is around the 8.4-8.5 range in the evening.. don't have a digital tester yet, just the test tube kind.. been holding off until i can afford a whole calcium reactor setup..

if i use less limewater and more of recipe #2 (which i'm using a 9:1 baking soda to baked baking soda; shooting for a 8.3 pH), in the long run the pH would be around 8.3.. is this still considered "high" for causing accelerated precipitation?

[Randy Holmes-Farley]

I didn't know that CaCO3 was less soluble at higher temperature.. when the temperature gets warmer, does it just precipitate in the water column?

No, the water temperature doesn't usually change enough (although if yuou put it on the stove it will).

I show the magnitude of the temperature effects in this article:

Calcium
http://www.advancedaquarist.com/issues/mar2002/chem.htm

i guess what i'm asking is, how does it know to harden onto heater/pumps instead of a snail's shell?

The pumps and heaters are hotter than the water.

in the long run the pH would be around 8.3..

It might be, but it might also be well off from that, depending on the details of the aquarium and the amount of CO2 in the air in youre home.

A pH of 8.3 is fine. The abiotic precipitation does not really get going strongly until the pH is above 8.5, as long as the other parameters are not too high.

[MarkBronder]

Does the build-up he has described require more frequent cleaning of pumps and their components. I am using magnesium, and two-part B-Ionic and have similar build-up. How often do you recommend cleaning pumps?

[Randy Holmes-Farley]

Yes, the abiotic precipitation is much of what you need to remove from pump impellers. How often to clean pumps is best determined by trial and error. If they slow down or sieze, it is obviously time to clean them. In many cases once a year may be fine.