Calcium-Alkalinity dosing issues

gpcady · 09/07/2006, 10:55 AM

Hello all,

I have been monitoring my tanks depletion of calcium and alkalinity so I can set up a dosing regimen. When the levels were at around 320 mg/L and 3.0 meq/L, the usage was about 15 mg/L and 0.25 meq/L (collected data over 4 days). I started dosing twice these amounts in order to get the levels up to 400 mg/L and 4.5 meq/L. Testing the levels 2 days later, the levels had not changed. The usage doubled. Is this typical - usage increases as the amount available increases? If so, by that much?

I am adding the calcium in the morning, and the alkalinity in the evening. I am using Seachem Reef Advantage Calcium and Reef Builder. Would it help to spread out the additions even more (as in not adding the calcium all at once)?

I have a 12" leather coral, about 10 golf to tennis ball size leathers, a hammer coral, and a tiny SPS. System capacity is about 80 gallons.

What are typical depletion rates folks are experiencing?

Thanks,

Greg

chip721 · 09/07/2006, 12:36 PM

What you're seeing doesn't sound too unusual. I'd also test Mg and continue measuring Ca and Alk for a few days to see if you can reach a point where they are balanced. Uptake "mileage-may-vary" from tank to tank due to inhabitants. If regular water changes don't suffice, IMO you might want to try a 2 part additive like B-Ionic, where you would (separately) dose equal amounts of each Ca and Alk. I would also run the questions by the Chemistry forum where you can get some answers from the experts.

jeffbrig · 09/07/2006, 12:52 PM

Greg, keep in mind that calcification slows down as calcium, alkalinity, and/or pH are lowered. At 320mg/L and 3.0meq/L you were definitely on the low side. When those levels are increased, I would expect to see some increase in calcification rates. How much, I can't quantify, but I would expect it to be higher.

As far as how much to add at once....I haven't used those exact products, and I'm not certain what they're composed of. In general, limit calcium additions to 25ppm increase per day. Any buffer/alkalinity dosing will typically be limited by pH change - try to keep it under .2 per addition, but you can add some every few hours as the short-term pH change dissipates.

(FWIW, I typically use a calcium chloride for Ca, and washing soda for Alk)

gpcady · 09/07/2006, 01:10 PM

Thanks guys,

I have not tested Mg - I have made the assumption this was maintained with water changes and additives (Seachem Calcium has mg and stronium). Am I missing an important test factor here?

Calcification has definately been an issue in the past, but I have not usually seen this high depletion rate increase until the tank is at about 5 meg/L. At that time, I was adding 1 meq/L a day, and still could not maintain a level. I will try spreading out the alk additions as recommended, perhaps this will reduce the calcification.

Calcium cloride... is that Kalkwasser? Any input on this as a solution?

Any input of which would be most advisable to add, calcium or alkalinity, to my auto top-off?

Thanks,

Greg

jeffbrig · 09/07/2006, 03:19 PM

All salt mixes contain magnesium, generally in sufficient amounts. Over time, you might notice a decline in Mg requiring a correction. This is also somewhat dependent on your chosen Ca/Alk supplementation scheme. If you have low Mg, you'll have problems maintaining proper Calcium.

Calcification is a good thing, being the process of corals/clams/etc building skeletons out of calcium and carbonate that they pull from the water. I think you're confusing the term with precipitation, which is an abiotic process where calcium carbonate forms on surfaces (pumps, heaters, etc.) in the tank.

Calcium Chloride (CaCl) is simply one of the standard Ca-only additives. It's packaged and sold under many brands for aquarium use, and also available in large bags (Dowflake brand) for use as a de-icer or pool additive.

You mentioned kalkwasser - that's calcium hydroxide, and balanced Ca and Alkalinity supplement. A balanced additive provides Ca and Alk in the same ratio that they are consumed by corals in your tank. Balanced additives are good things. If you choose to use non-balanced additives (like those I mentioned above), you must carefully measure your levels and make sure you are adding each element appropriately. Make sure you know what you're doing if you go this route.

If you're going to add something to your topoff, kalkwasser is probably the easiest choice. It has a tendency to elevate pH, which is a good thing for most tanks. Adding calcium or alkalinity alone in your topoff would cause your water chemistry to become unbalanced. Not good!

gpcady · 09/07/2006, 06:02 PM

Thanks again,

I think I shall buy a Mg test kit, and look into Kalkwasser, then. I have thought about it before, but not having an auto top-off reservoir, I determined it was not the way to go. Any have any thoughts/concerns with Kalkwasser?

09/07/2006, 10:55 AM	#1
gpcady Registered Member Join Date: Sep 2004 Location: Bellingham Posts: 18	Calcium-Alkalinity dosing issues Hello all, I have been monitoring my tanks depletion of calcium and alkalinity so I can set up a dosing regimen. When the levels were at around 320 mg/L and 3.0 meq/L, the usage was about 15 mg/L and 0.25 meq/L (collected data over 4 days). I started dosing twice these amounts in order to get the levels up to 400 mg/L and 4.5 meq/L. Testing the levels 2 days later, the levels had not changed. The usage doubled. Is this typical - usage increases as the amount available increases? If so, by that much? I am adding the calcium in the morning, and the alkalinity in the evening. I am using Seachem Reef Advantage Calcium and Reef Builder. Would it help to spread out the additions even more (as in not adding the calcium all at once)? I have a 12" leather coral, about 10 golf to tennis ball size leathers, a hammer coral, and a tiny SPS. System capacity is about 80 gallons. What are typical depletion rates folks are experiencing? Thanks, Greg

09/07/2006, 12:52 PM	#3
jeffbrig Premium Member Join Date: Mar 2004 Location: Ft. Lauderdale, FL Posts: 5,548	Greg, keep in mind that calcification slows down as calcium, alkalinity, and/or pH are lowered. At 320mg/L and 3.0meq/L you were definitely on the low side. When those levels are increased, I would expect to see some increase in calcification rates. How much, I can't quantify, but I would expect it to be higher. As far as how much to add at once....I haven't used those exact products, and I'm not certain what they're composed of. In general, limit calcium additions to 25ppm increase per day. Any buffer/alkalinity dosing will typically be limited by pH change - try to keep it under .2 per addition, but you can add some every few hours as the short-term pH change dissipates. (FWIW, I typically use a calcium chloride for Ca, and washing soda for Alk) __________________ Beware the power of stupid people in large groups..... Current Tank Info: formerly 250g room divider

09/07/2006, 03:19 PM	#5
jeffbrig Premium Member Join Date: Mar 2004 Location: Ft. Lauderdale, FL Posts: 5,548	All salt mixes contain magnesium, generally in sufficient amounts. Over time, you might notice a decline in Mg requiring a correction. This is also somewhat dependent on your chosen Ca/Alk supplementation scheme. If you have low Mg, you'll have problems maintaining proper Calcium. Calcification is a good thing, being the process of corals/clams/etc building skeletons out of calcium and carbonate that they pull from the water. I think you're confusing the term with precipitation, which is an abiotic process where calcium carbonate forms on surfaces (pumps, heaters, etc.) in the tank. Calcium Chloride (CaCl) is simply one of the standard Ca-only additives. It's packaged and sold under many brands for aquarium use, and also available in large bags (Dowflake brand) for use as a de-icer or pool additive. You mentioned kalkwasser - that's calcium hydroxide, and balanced Ca and Alkalinity supplement. A balanced additive provides Ca and Alk in the same ratio that they are consumed by corals in your tank. Balanced additives are good things. If you choose to use non-balanced additives (like those I mentioned above), you must carefully measure your levels and make sure you are adding each element appropriately. Make sure you know what you're doing if you go this route. If you're going to add something to your topoff, kalkwasser is probably the easiest choice. It has a tendency to elevate pH, which is a good thing for most tanks. Adding calcium or alkalinity alone in your topoff would cause your water chemistry to become unbalanced. Not good! __________________ Beware the power of stupid people in large groups..... Current Tank Info: formerly 250g room divider

09/07/2006, 12:36 PM	#2
chip721 Premium Member Join Date: Jan 2005 Location: Alexandria, Virginia Posts: 1,260	What you're seeing doesn't sound too unusual. I'd also test Mg and continue measuring Ca and Alk for a few days to see if you can reach a point where they are balanced. Uptake "mileage-may-vary" from tank to tank due to inhabitants. If regular water changes don't suffice, IMO you might want to try a 2 part additive like B-Ionic, where you would (separately) dose equal amounts of each Ca and Alk. I would also run the questions by the Chemistry forum where you can get some answers from the experts.

09/07/2006, 01:10 PM	#4
gpcady Registered Member Join Date: Sep 2004 Location: Bellingham Posts: 18	Thanks guys, I have not tested Mg - I have made the assumption this was maintained with water changes and additives (Seachem Calcium has mg and stronium). Am I missing an important test factor here? Calcification has definately been an issue in the past, but I have not usually seen this high depletion rate increase until the tank is at about 5 meg/L. At that time, I was adding 1 meq/L a day, and still could not maintain a level. I will try spreading out the alk additions as recommended, perhaps this will reduce the calcification. Calcium cloride... is that Kalkwasser? Any input on this as a solution? Any input of which would be most advisable to add, calcium or alkalinity, to my auto top-off? Thanks, Greg

09/07/2006, 06:02 PM	#6
gpcady Registered Member Join Date: Sep 2004 Location: Bellingham Posts: 18	Thanks again, I think I shall buy a Mg test kit, and look into Kalkwasser, then. I have thought about it before, but not having an auto top-off reservoir, I determined it was not the way to go. Any have any thoughts/concerns with Kalkwasser?