Dosing Kalk correctly to top off water

[Thunder3]

I have been adding 1/2 teaspoon in 1 gallon RODI water and adding 1/2 of the gallon in the morning and the other 1/2 of the gallon at night for top off. It keeps my SG between 1.0256 and 1.0265. My calcium according to API liquid is 500 (25 drops) and Alk is 11. Should I lower the amount of kalk I use in the top off water to lower the calcium level in the tank hopefully to about 450?

[SnowboardKid26]

What corals do you keep? if you dont have alot of sps thats using the calcium then its just going to keep building. You could continue to dose kalk at night, but just add plain ro/di water in the morning and see how that works for a week or so. Your cal and alk levels are kind of high. That's what I would try.

[brad_G]

How big is the system? A half gallon of kalk in one whack seems like it would cause a significant Ph swing.

[Thunder3]

I like the idea about 1/2 gallon just RODI in morning and 1/2 gallon with kalk at night. I could do this or just lower the overall amount of kalk I add to the gallon of RODI to maybe 1/4 of a teaspoon and continue adding morning and night. I have a 75 gallon tank with mainly LPS & softies only 1 little montipora

[SnowboardKid26]

+1 on PH swings. Are you monitoring PH while adding the kalk?

[Thunder3]

yes my ph stas about 8 in morning to about 8.3 later in day. I have Chaetomorpha in refugium in sump with light on at the night.

[barjam]

What corals do you keep? if you dont have alot of sps thats using the calcium then its just going to keep building. You could continue to dose kalk at night, but just add plain ro/di water in the morning and see how that works for a week or so. Your cal and alk levels are kind of high. That's what I would try.

It won't keep on building as it will form calcium carbonate and coat his heater and lock up his pumps. :)

[Thunder3]

It won't keep on building as it will form calcium carbonate and coat his heater and lock up his pumps. :)



What do you mean by won't keep on building and coat heater?

[disc1]

What do you mean by won't keep on building and coat heater?

Calcium and alkalinity don't like to be dissolved at the same time. They would rather get together and form calcium carbonate. If you get calcium and alkalinity too high they will suddenly start precipitating out and leaving a white haze on everything. Warmer temps make it happen faster so it tends to happen first on heaters and pumps.

[Thunder3]

Should I do the top off with kalk at night and just plain RODI in morning method or lower the amount of kalk from 1/2 teaspoon to 1/4 teaspoon per 1 gallon of RODI water.

[SnowboardKid26]

I would actually just top off with RO/DI until your levels come down

[thegrun]

Kalk will not raise your alkalinity or calcium, only maintain them at their current levels. You might quit adding kalk altogether until your calcium and alkalinity drop to your desired levels and then return to your current dosing regiment, although i also would worry about large PH swings. Using an Automatic Top Off system would dose much smaller amounts of kalkwasser at a time and reduce the PH swings.

[Thunder3]

I have no room for a ATO in the sump area. I still think that adding kalk does increase the calcium besides maintaining it??? Maybe just add RODI morning and night till I get the calcium lowered then either the lowered amount of kalk in top off water or kalk at night and RODI water in morning

[disc1]

If the tank has very little consumption by corals and corraline algae then dosing kalk will cause levels to slowly rise. In most of those types of situations there would be no need to dose anything but rather use regular water changes to keep parameters in line.

[Thunder3]

I like the added benefit of kalk that it removes or precipitates phosphates from the tank.

[rcypert]

How old is the tank? How long have you been doing this? Is there anything causing concern? Dosing a quarter teaspoon in a 75 is fine. I believe Randy Holmes Farley discusses kalk dosing in a slurry where he says 1/4 teaspoon per 100 gallons should be fine so for 75 it a bit more risky but I dose that much all at once in my 58 and its good. I wouldn't drastically change your dosing schedule unless something is wrong. Cutting the kalk all together might do more harm then good. If your really worried just reduce it a little bit. If the tank is good and everything looks great keep going. Just watch for carbonate build up and if your levels keep getting higher then obviously reduce kalk dosing.