Excessive calcium carbonate w/Balanced parameters

[gdemos]

With a calcium reactor running at high throttle 125 ml/min plus a kalk top off I'm keeping steady 8-9.6 dKh and 420-435 ppm ca Mg at 1450-1500 all salifert. System is 75g all acro frag tank, 50+ frags few fish. Live rock in sump heavily skimmed high flow temp controlled 80.5-81.5

I'm getting what I'd call excessive calcium carbonate build up. For example if I go 4 months without cleaning pumps thoroughly I get nervous.

Many may say I'm running the reactor at too much effluent but it keeps things stable at this rate

Effluent dKh at 12

Any thoughts? I really don't like the carbonate build up but I know that citing back on the reactor will lose pace

Thanks,
Greg

 

[Randy Holmes-Farley Verified Community Expert]

The things one can do to reduce calcium carbonate buildup are to reduce alkalinity, calcium, and pH, and raise magnesium.

I wouldn't raise magnesium further, and calcium looks fine.

pH is likely OK, but what is it?

Dosing the limewater (kalkwasser) well away from pumps is also recommended.

Dropping the alk back to 7-8 dKH would likely help.

 

[gdemos]

Kalk tops off adjacent to effluent of CaRx and right by a big koralia in sump, pH runs lower than if like 7.8-8.1 with a recently calibrated probe. My kalk mix is heavy 1.5+. Tsp per gal

 

[Randy Holmes-Farley Verified Community Expert]

Kalk tops off adjacent to effluent of CaRx and right by a big koralia in sump, pH runs lower than if like 7.8-8.1 with a recently calibrated probe. My kalk mix is heavy 1.5+. Tsp per gal

How fast is the limewater added?

 

[gdemos]

I can't say precisely. My top off barrell is 55g and it feeds my 225g system plus this 75 g system in discussion. Fwiw probably throwing 30 g every 10 days to the two sumps. For this system I might say 1g per day via mechanical float switch - gravity fed.

 

[Randy Holmes-Farley Verified Community Expert]

I can't say precisely. My top off barrell is 55g and it feeds my 225g system plus this 75 g system in discussion. Fwiw probably throwing 30 g every 10 days to the two sumps. For this system I might say 1g per day via mechanical float switch - gravity fed.

I was thinking in terms of the limewater dose given with a single activation of the float switch. If you dose too much at once, the pH will get very high and cause precipitation, either locally where you dose, or even in the whole tank, even if the other parameters are all fine an hour later.

Adding 1.25% of the sump volume at once will boost that sump pH by about 0.6-0.7 pH units, which could easily cause precipitation in the sump, for example.

 

[gdemos]

There have been a couple occasion where the float switch sticks and I get a dramatic dose but for the most part it is mechanically metered.

 

[gdemos]

I take a toothbrush to the floats daily. Just to be sure the flow works and in so doing I give the sump a shot of kalk. But we're only talking maybe 10mL.

 

[Randy Holmes-Farley Verified Community Expert]

10 mL seems OK unless it is dosed right in frot of a pump or to a very small sump volume.

Many people uses systems where it drips for this reason, either by "dripper" or by very slow pump. I use a pump that at max rate delivers a few gallons a day (which is close to a drip).