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Palting
12/10/2010, 06:40 PM
I've read and re-read, and I'm getting more and more confused and confounded.

Tank is in my sig. I do 10% WC weekly with Reef Crystals. I do not dose. I use Salifert for testing. Calcium is 440 and alk is 11 dKH in the new water. Tank water is Calcium 440, alk 7 dKH, pH 8.0-8.2. After WC, tank water Ca is 440, Alk 7.4-7.6 dKH. One week later, the alk is back down to 7 dKH. Today, it may even be 6.7, one drop difference from 7.0.

Rest of the parameters: SG 1.026 (refractometer), Ammonia/nitrite/nitrate 0 (IO ReefMaster), temp 79-80. I don't have a test for Mag.

Weird thing is, my sps are gowing, as are the lps who are fat. Of all the livestock that I have, it's the colt coral, the easiest of them all, that seems to be having a hard time.

Thanks for any help. I am confused and frustrated.

jdaniels175
12/10/2010, 06:52 PM
Mg levels make a difference in being able to maintain your ALK. As to why your ALK is dropping, it probably has a lot to do with your statement "my SPS are growing". And here's my $.02 about the subject: If it aint broke don't fix it. I just went through this same thing and am now dealing with the aftermath of trying to mess with the ALK. If you are convinced you need to raise it, test like crazy until you get a handle on how much ALK you need to add to maintain a higher level, and then keep on top of it.

bertoni
12/10/2010, 11:38 PM
The dKH in many tanks drops 2-3 dKH per day, especially with stony corals, clams, or coralline algae that's active. You might need to start dosing if you want to maintain a high growth rate, or even basic coral health.

langtudatinh01
12/11/2010, 12:43 AM
yup, i have same time before dosing. since added a clam and sps, my alk was out of control until i started to dose pure baking soda (daily now). since then my stony corals are doing very good and the clam too. my only stay around 8.

Toadally
12/11/2010, 07:34 AM
Having to dose alk and cal is a good thing. It means your corals and system as a whole are using it and your animals are growing. I went through a spell were things were stagnant and growth was very slow, so alk and ca were easily maintained. Now things are taking off again and I like the fact that I have to keep adding more and more alkalinity and calcium. Good luck!

Palting
12/11/2010, 12:21 PM
Thank you for the replies!

I would have thought the calcium would have gone down as well if this was consumption for coral growth, no?

Ok, I have several options on what to use for dosing, if you guys think I should start dosing. I have Kent Marine Pro buffer (buffer only), a product called Kalk Plus2 by Brightwell Aquatics (kalkwasser with added mag, strontium, etc), and I can deliver these with a Aquadoser drip. Since the calcium remains rock steady at 440, I was thinking I should only dose the buffer, yes? I'll keep an eye on the calcium, and start dosing ca only when the water changes can no longer keep up with consumption, right?

Tbduval
12/11/2010, 05:51 PM
I think you will want to start some sort of balanced dosing schedule ex. 2-part, kalk, calcium reactor. If ALK drops 1 meq/l your calcium will drop 20ppm. There is enough test noise in calcium test kits to not see the drop during testing until the level has dropped beyond your target. I would not dose just ALK. You levels might shift more than desired and you will always be trying to correct one or the other.

By taking taking the balance ALK and calcium route, you will replace your demand equally and your parameters will not shift very much.

Toadally
12/11/2010, 06:52 PM
i think you will want to start some sort of balanced dosing schedule ex. 2-part, kalk, calcium reactor. If alk drops 1 meq/l your calcium will drop 20ppm. There is enough test noise in calcium test kits to not see the drop during testing until the level has dropped beyond your target. I would not dose just alk. You levels might shift more than desired and you will always be trying to correct one or the other.

By taking taking the balance alk and calcium route, you will replace your demand equally and your parameters will not shift very much.

+1

bertoni
12/11/2010, 08:35 PM
I agree that a 2-part is a good way to get started. The kalk will be okay, although the magnesium part won't work. The high pH of kalk causes magnesium hydroxide to precipitate. I'm not sure whether the strontium will be useful. Generally, it doesn't seem to be:

http://www.advancedaquarist.com/issues/nov2003/chem.htm

twintrades
12/11/2010, 08:45 PM
I have the same problem and its my Magneesium. I have to dose the tank to get back to the 1250 ppm. Then once there the alk seems to be more stable. I could have dosed alk to the tank and in a few hrs it wouldnt show any diff on a test.

I had the problem Before. but for some reason i quit dosing the Mag. Dont ask why i could'nt tell ya.

Palting
12/11/2010, 09:05 PM
Although it seems upstream, I think I'm making some headway into understanding. Thanks, guys. Looks like it's time to look into 2 part dosing. I'm actually psyched! Something new to learn and do!!

iamwrasseman
12/11/2010, 10:31 PM
do not over do the dosing and there is a calculator here on RC on the home page to help you out .you should test for mag or you may have difficulty getting things stable . mag should be 3x calcium . you ca is at 440 so you optimally are going to shoot for 1320 on your mag then the alk should raise naturally . if not then start your dosing and do any changes slowly and watch your corals as they will tell you when they are happy .
good luck

tmz
12/11/2010, 10:52 PM
Anything over 1300 and under 1500ppm for mag is ok ,ime.

BTW, to answer an earlier question. Yes, calcium is used along with carbonate alkalinity as calcifying organisims including stony corals coraline, molusks, etc, precipitate calcium carbonate to form skeletal mass. Both are also used when abiotic precipitation of calcium carbonate occurs. The thing is :for every 20ppm of calcium used; a whopping 2.8 dkh of carbonate alkalinity is used. So, it is common to notice alkalinity drops( 8 dkh to 5dkh for example) while calcium use (450 to 430 ppm for example) often
slips under the radar as testing variation with hobby test kits since there is relatively little of it used.

iamwrasseman
12/11/2010, 10:56 PM
tmz good explanation there ! sometimes its hard to explain but that made it easy for him ~or her

Grant W
12/11/2010, 11:06 PM
tmz +1 on the good explanation. I have often wondered why my alk would drop so much. Nice piece of info on consumption.

tmz
12/11/2010, 11:21 PM
Thanks, Glad it helped.

Palting
12/12/2010, 08:19 AM
Yes, that cleared that up well. Thanks, tmz!