MCsaxmaster
New member
I aim to please :thumbsup:
Let's talk about Alkalinity, Calcium and Magnesium in an SPS Tank
- Thread starter JB NY
- Start date
MCsaxmaster
New member
Yeah, that's probably not bad. For magnesium I'd shoot for right around NSW levels: 1250-1350 ppm seems appropriate (NSW ~1285 ppm). There's no reason to think higher magnesium is actually doing anything good, while low magnesium can cause excessive abiotic CaCO3 precipitation problems.
For calcium I'd shoot for at or perhaps just slightly higher than NSW: 400-450 ppm seems appropriate (NSW ~ 412 ppm). There's very little reason to think that calcium higher than that actually encourages faster calcification in most corals. Below 400 ppm, however, you may start running into calcium limitation of calcification, but calcification is only reduced slowly from ~400 down to maybe ~300 ppm. From 300 to 200 ppm calcifcation drops off much faster. Below 200 ppm calcification drops like a rock.
I'd maintain a minimum of 7 dKH total alkalinity (assuming normal borate levels). NSW has ~6.6 dKH total alk. Critters do just fine in that, but most certainly calcify faster with higher alk. I've generally had the best success maintaining TA in the neighborhood of 9-12 dKH.
Oh, and the NSW parameters all assume standard sea water (35 ppt, 25 C, 1 atm, etc.).
Chris
For calcium I'd shoot for at or perhaps just slightly higher than NSW: 400-450 ppm seems appropriate (NSW ~ 412 ppm). There's very little reason to think that calcium higher than that actually encourages faster calcification in most corals. Below 400 ppm, however, you may start running into calcium limitation of calcification, but calcification is only reduced slowly from ~400 down to maybe ~300 ppm. From 300 to 200 ppm calcifcation drops off much faster. Below 200 ppm calcification drops like a rock.
I'd maintain a minimum of 7 dKH total alkalinity (assuming normal borate levels). NSW has ~6.6 dKH total alk. Critters do just fine in that, but most certainly calcify faster with higher alk. I've generally had the best success maintaining TA in the neighborhood of 9-12 dKH.
Oh, and the NSW parameters all assume standard sea water (35 ppt, 25 C, 1 atm, etc.).
Chris
Marshall Haith
Reefer
I don't think this issue has been discussed.
Problem: annoying buildup of what looks like calcium precipitate on glass (white chalky stuff that is hard to scrape off), mainly, but not exclusively, on sides where the flow from the power heads is directed and on front middle glass where the flow from the two heads meets.
Parameters:
50 g tank, 5 g sump
ph around 8.0
calc around 325
dkh around 6.5 to 7.0
mag at around 1280-1300
water changes of 8% or so/week
light coral load
Trying to raise calc to around 425 without much luck. I'm using 2-part solution, adding 100 ml of calc/day and 100 ml of buffer. These are added in 50 ml doses. each in about a half liter of water, to sump through a gravity drip at around 2 drips/sec.
The values are around 2.5X what I think Randy suggests for this size and type of tank, but the calcium level isn't changing much (after about 2 gals of mix have been added over several weeks). The precipitate is terribly annoying and time consuming to remove and suggests that I may be adding too much. I've checked the calk, ph and dkh measures against store measures and my son's kits.
The heater glass did have a substantial buildup, but I cleaned it two weeks ago, and it doesn't seem to be accumulating a film very quickly. I haven't checked the pumps internally, but they don't look bad at all on the outside.
Befuddled.
Problem: annoying buildup of what looks like calcium precipitate on glass (white chalky stuff that is hard to scrape off), mainly, but not exclusively, on sides where the flow from the power heads is directed and on front middle glass where the flow from the two heads meets.
Parameters:
50 g tank, 5 g sump
ph around 8.0
calc around 325
dkh around 6.5 to 7.0
mag at around 1280-1300
water changes of 8% or so/week
light coral load
Trying to raise calc to around 425 without much luck. I'm using 2-part solution, adding 100 ml of calc/day and 100 ml of buffer. These are added in 50 ml doses. each in about a half liter of water, to sump through a gravity drip at around 2 drips/sec.
The values are around 2.5X what I think Randy suggests for this size and type of tank, but the calcium level isn't changing much (after about 2 gals of mix have been added over several weeks). The precipitate is terribly annoying and time consuming to remove and suggests that I may be adding too much. I've checked the calk, ph and dkh measures against store measures and my son's kits.
The heater glass did have a substantial buildup, but I cleaned it two weeks ago, and it doesn't seem to be accumulating a film very quickly. I haven't checked the pumps internally, but they don't look bad at all on the outside.
Befuddled.
MCsaxmaster
New member
Huh--could you post a picture? Accumulating preferentially in areas of strong flow sems strange.
cj
cj
Aquarist007
New member
I agree with your statements.
Corals actually don't use that much magnesium--regular water changes with the appropriate salt mix can help keep the mag up
Look at the differences in levels in the different mixes that Billybeau has put together
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1287118
Marshall Haith
Reefer
calcium on glass
calcium on glass
Huh--could you post a picture? Accumulating preferentially in areas of strong flow seems strange.
c j
Thanks Chris. Posted are a couple of photos, the closeup being of the center front glass. You are right. The calc buildup is actually to the side of the powerheads and below them, not in the output stream, so the water is pretty slow-moving there. In front, the output streams from the two powerheads meet, so they cancel one another, and the flow is pretty slow there also.
mh
calcium on glass
Huh--could you post a picture? Accumulating preferentially in areas of strong flow seems strange.
c j
Thanks Chris. Posted are a couple of photos, the closeup being of the center front glass. You are right. The calc buildup is actually to the side of the powerheads and below them, not in the output stream, so the water is pretty slow-moving there. In front, the output streams from the two powerheads meet, so they cancel one another, and the flow is pretty slow there also.
mh
Aquarist007
New member
Re: calcium on glass
Re: calcium on glass
<img src="/images/welcome.gif" width="500" height="62"><br><b><i><big><big>To Reef Central</b></i></big></big>
could you possible take out an album on www.photobucket.com
you upload your pictures to your album
under each pic is four codes
you use the fourth code----the "img" code to copy and paste into your posts
You get a much bigger and clearer picture when doing that then using the gallery here.
Re: calcium on glass
<a href=showthread.php?s=&postid=12772714#post12772714 target=_blank>Originally posted</a> by Marshall Haith
Huh--could you post a picture? Accumulating preferentially in areas of strong flow seems strange.
c j
Thanks Chris. Posted are a couple of photos, the closeup being of the center front glass. You are right. The calc buildup is actually to the side of the powerheads and below them, not in the output stream, so the water is pretty slow-moving there. In front, the output streams from the two powerheads meet, so they cancel one another, and the flow is pretty slow there also.
mh
<img src="/images/welcome.gif" width="500" height="62"><br><b><i><big><big>To Reef Central</b></i></big></big>
could you possible take out an album on www.photobucket.com
you upload your pictures to your album
under each pic is four codes
you use the fourth code----the "img" code to copy and paste into your posts
You get a much bigger and clearer picture when doing that then using the gallery here.
Marshall Haith
Reefer
calcium precipitation
calcium precipitation
Ok, here they are.
mh
[/IMG]
[/IMG]
calcium precipitation
Ok, here they are.
mh
Aquarist007
New member
had the same problem last summer. I keep a window open in the basement 24/7. That kept not following below 8.0.This spring I added a second 37 gal fuge--that keeps the pH at 8.19
If you can't keep the window open vent the skimmer to the outside--that will make a difference
Aquarist007
New member
Re: calcium precipitation
Re: calcium precipitation
much better
I would assume your low dkH values are behind the precipitation
You should be running 10-11.5 dkH
Re: calcium precipitation
<a href=showthread.php?s=&postid=12774694#post12774694 target=_blank>Originally posted</a> by Marshall Haith
Ok, here they are.
mh
[/IMG]
[/IMG]
much better
I would assume your low dkH values are behind the precipitation
You should be running 10-11.5 dkH
Marshall Haith
Reefer
Hmm. I was using this article by Randy Holmes-Farley as a guide: http://reefkeeping.com/issues/2005-07/rhf/index.php. The article indicates that increasing alk exacerbates the problem of calc precipitation, so I was shooting for the lower end of the operating range for alk.
mh
Aquarist007
New member
but at what levels did you get the precipitation?
IMO keeping the alk between 8-11 is better then keeping it in the low 7's?
I am sure Randy mentioned something about low alkalinity
IMO keeping the alk between 8-11 is better then keeping it in the low 7's?
I am sure Randy mentioned something about low alkalinity
Marshall Haith
Reefer
Actually, I've had the dkh in the 8-10 range, and I had the same problem.
mh
mh
MCsaxmaster
New member
Marshall,
How are you measuring pH?
I would assume your low dkH values are behind the precipitation
Huh-uh. All else equal (e.g., pH, temperature, precense of nucleation sites, etc.), with lower carbonate alkalinity you'll have lower rates of CaCO3 precipitation.
The rate of precipitation depends mostly on saturation state (assuming there are available nucleation sites, which is probably a good assumption in an aquarium full of pieces of CaCO3 rock/sand ). Saturation state, at a given temperature, salinity, pressure, is described by:
omega = [Ca++][CO3=]/Ksp*
where [Ca++] is the calcium concentation, [CO3=] is the carbonate concetration, and Ksp* is the solubility product (adjusted for use in sea water). If calcium goes up, satuation state goes up proportionally. If carbonate goes up, saturation state goes up proportionally. Carbonate concentration is controlled by carbonate alkalinity and pH (all else equal). The higher the alkalinity, all else equal, the more carbonate there is. The higher the pH, all else equal, the more carbonate there is. If both alkalinity and pH go up, carbonate goes up more still. You get the idea.
How are you measuring pH?
I would assume your low dkH values are behind the precipitation
Huh-uh. All else equal (e.g., pH, temperature, precense of nucleation sites, etc.), with lower carbonate alkalinity you'll have lower rates of CaCO3 precipitation.
The rate of precipitation depends mostly on saturation state (assuming there are available nucleation sites, which is probably a good assumption in an aquarium full of pieces of CaCO3 rock/sand
). Saturation state, at a given temperature, salinity, pressure, is described by:omega = [Ca++][CO3=]/Ksp*
where [Ca++] is the calcium concentation, [CO3=] is the carbonate concetration, and Ksp* is the solubility product (adjusted for use in sea water). If calcium goes up, satuation state goes up proportionally. If carbonate goes up, saturation state goes up proportionally. Carbonate concentration is controlled by carbonate alkalinity and pH (all else equal). The higher the alkalinity, all else equal, the more carbonate there is. The higher the pH, all else equal, the more carbonate there is. If both alkalinity and pH go up, carbonate goes up more still. You get the idea.
Aquarist007
New member
<a href=showthread.php?s=&postid=12781414#post12781414 target=_blank>Originally posted</a> by MCsaxmaster
Marshall,
How are you measuring pH?
I would assume your low dkH values are behind the precipitation
Huh-uh. All else equal (e.g., pH, temperature, precense of nucleation sites, etc.), with lower carbonate alkalinity you'll have lower rates of CaCO3 precipitation.
The rate of precipitation depends mostly on saturation state (assuming there are available nucleation sites, which is probably a good assumption in an aquarium full of pieces of CaCO3 rock/sand
omega = [Ca++][CO3=]/Ksp*
where [Ca++] is the calcium concentation, [CO3=] is the carbonate concetration, and Ksp* is the solubility product (adjusted for use in sea water). If calcium goes up, satuation state goes up proportionally. If carbonate goes up, saturation state goes up proportionally. Carbonate concentration is controlled by carbonate alkalinity and pH (all else equal). The higher the alkalinity, all else equal, the more carbonate there is. The higher the pH, all else equal, the more carbonate there is. If both alkalinity and pH go up, carbonate goes up more still. You get the idea.
gottcha---thanks very much for the detailed answer:smokin:
gary faulkner
New member
Capn,
Sounds Greek to me too.
MCsaxmaster
New member
Greek, geek, whatever
