Kalk Theoretical Chemistry Question

andrewey

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A few years ago I ran an experiment and dosed saturated kalk via my ato in a nano with only a few frags. Previous tests on this tank confirmed that the calcium requirements were minimal and that "full strength" saturated lime water would be excessive. I started dosing and as predicted, both my calcium and alkalinity levels increased, but seemed to level off after a month or so. I expected to eventually encounter calcium precipitation of some sort, however this never materialized after three months I'm not sure if I ran my experiment long enough or if my predicted endpoints were wrong, so I wanted to pose the following question:

In a theoretical reef aquarium without any livestock, what would be the effect of dosing saturated limewater long term (where ph and salinity are held constant)? Would the calcium and alkalinity levels simply continue to rise in tandem, would calcium precipitation eventually occur, would some type of equilibrium be reached, etc. For the purposes of this question, the saturated lime water would be dosed in a high flow area at a very slow drip.
 
In a theoretical reef aquarium without any livestock, what would be the effect of dosing saturated limewater long term (where ph and salinity are held constant)?

if you mean no fish or coral or anyother life,;that would be a very easy experiment to conduct.​
 
A few years ago I ran an experiment and dosed saturated kalk via my ato in a nano with only a few frags. Previous tests on this tank confirmed that the calcium requirements were minimal and that "full strength" saturated lime water would be excessive. I started dosing and as predicted, both my calcium and alkalinity levels increased, but seemed to level off after a month or so. I expected to eventually encounter calcium precipitation of some sort, however this never materialized after three months I'm not sure if I ran my experiment long enough or if my predicted endpoints were wrong, so I wanted to pose the following question:

In a theoretical reef aquarium without any livestock, what would be the effect of dosing saturated limewater long term (where ph and salinity are held constant)? Would the calcium and alkalinity levels simply continue to rise in tandem, would calcium precipitation eventually occur, would some type of equilibrium be reached, etc. For the purposes of this question, the saturated lime water would be dosed in a high flow area at a very slow drip.

I dosed it as the only source of calcium and alkalinity (aside from 1% daily water changes) for 20 years, and my tank was fine. :)

Demand by both corals and abiotic precipitation rises as both pH and alk and calcium rise, so the levels do not keep rising but would typically level off as you found. Alk will rise much more than calcium, on a percentage basis. Obviously if the dosing is quite excessive there will be abiotic precipitation that might be visible somewhere. I only ever saw it in gross overdose events, except for the normal precipitation on pumps and heaters, etc..

The only theoretical "concern" with limewater dosing is the calcium slowly rises if you use limewater to exactly maintain alkalinity because it is very slightly overbalanced to extra calcium (because magnesium and strontium take the place of some calcium in the deposited calcium carbonate).
 
Randy,

Thanks for the answer- it's everything I was looking for!
 

IF YOU HAD TO TAKE A REEFING EXAM, WOULD YOU PASS?

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