Reef Alkalinity / Calcium levels

[Floyd R Turbo]

I have a question regarding my water parameters for this tank

http://www.aquariumadvice.com/forums/f11/tank-journal-125-reef-125546.html

I have been consistently testing and recording for about a year. Over the last 3 months, I have made some major changes to the system, mainly added a bunch of LR and corals and have noticed the effects on the levels.

I have been adding Brightwell Aquatics Alkalin8.3-P to raise alkalinity in doses of 4g (1 tsp) mixed with RO water, and Seachem Reef Advantage Calcium to raise Calcium (along with Magnesium and Strontium, but mainly Ca).

Below is my test log and other pertinent information since right before adding the bulk of the new LR and corals. Prior to that, I was maintaining the KH between 9.0 and 10.5 by added the buffer to the top off water, then decided to stop that and monitor and add manually to get a grasp on the level changes.

The items in Red Bold are when I added Seachem Reef Advantage Calcium. I figured out that 3 tsp / 12g of the Seachem stuff raises the Ca by about 10 points.

The items in Black Bold are when I added Brightwell Alkalin8.3-P. I have figured out that it raises the KH about 2x what the label directions say it does. So adding 1 tsp / 4g raises the alkalinity by approximately 1.2-1.5.

I always add the powder to a dry, empty 1 QT container, then pour RO water in, cap it, and shake well before adding to sump.

Here is the log:

8/19: KH = 11.2-11.3, Ca = 360-370, Mg = 1190-1210
8/20: Added roughly 50lb Live Rock & mushrooms, zoas (3), green polyps, frogspawn, 3 fish, did 18% PWC (20 g)
8/22: KH =11.2-11.3, Ca = 370-375, Mg = 1170-1210
8/24: KH = 10.4, Ca = 350-360. Added 12g Calcium
8/25: Ca = 360-365. Added 12g Calcium
8/26: KH = 10.2-10.4, Ca = 375-380. Added 12g Calcium
9/1: KH = 9.3-9.5, Ca = 375-385, Mg = 1185-1200. Added 12g Calcium
9/2: Added 12g Calcium
9/9: KH = 7.7-8.0, Ca = 400-405, Mg = 1200-1230. Added 8g KH Buffer
9/10: KH = 9.0-9.3
9/12: Rearranged tank (4 hours). Did 18% PWC (20 g)
9/13: KH = 9.0-9.1, Ca = 390, Mg = 1180-1200. Added 12g Calcium
9/15: Added 4g KH Buffer
9/16: KH = 9.3-9.4, Ca = 395. Added 12g Calcium.
9/24: KH = 7.7-8.0, Ca = 405-410, Mg = 1210-1230. Added 4g KH Buffer
9/26: 8.0-8.3, 10% PWC & fish added
9/27: KH = 8.3-8.6, Ca = 405-410, Mg = 1140. Added 12g Calcium
10/4: KH = 7.2-7.4, Ca = 430-460, Mg = 1200-1230
10/5: Added 4g KH Buffer
10/10: Changed to ATS, removed skimmer & filter sock system
10/11: added 10-15 pound Live Rock
10/12: KH = 7.4, Ca = 430-440, Mg = 1200. Added 4g KH Buffer
10/14: KH = 8.3, Ca = 430
10/16: added 5g saltwater (to raise sump level)
10/18: KH = 7.4-7.7, Ca = 450. Added 4g KH Buffer
10/21: Added 7-head Dendro & Trumpet Coral
10/22: KH = 7.7-8.0. Added 4g KH Buffer
10/25: KH = 7.0-7.4, Ca = 450, Mg = 1230-1260, Iodide = 0.01, Iodide+Iodate = ?, Strontium = 0-3. Added 4g KH Buffer. Topped off w/RO 2.5g once in afternoon, once in evening to lower salinity & raise sump level. Salinity was at 37 at “minimum” point on sump (top of pump exposed)
10/26: KH = 7.4-7.7. Added 4g KH Buffer, topped off 2.5g RO
10/27: KH = 8.3, salinity “ideal” point established and marked on sump = 35
10/29: KH = 7.7, Ca = 410. Added 12g Calcium.
11/1: KH = 6.7, Ca = 430. Added 4g KH Buffer. Topped off 0.5 gal RO.
11/2: KH = 7.5-7.7, Salinity = 36. Added 4g KH Buffer. Topped off 3g RO.

As you can see, I spent about 3 weeks (8/24 - 9/13) slow ratcheting the Calcium up to the low-mid 400s. Since then it really hasn't dropped much at all.

The Alkalinity seems to drop rather rapidly, in fact, if I go more than 3 or 4 days without adding the buffer, it drops below 7 and I have to dose it 2 days or more in a row, meanwhile Calcium hardly seems to fluctuate at all.

I also realize that when I stop in to check on the tank, I take my sample and then top the tank off if it needs it (it usually does), so immediately my sample is outdated, but I stay consistent with that practice, so the samples are well mixed and stable.

I would think that I would see more of a calcium drop with all the corals in the system. Am I missing something?

Current pics of the tank for coral reference:

and a quick list:

30-40 Xenia
huge Anthelia colony
Sun Polyp
Green Polyps
Purple, Green, Spotted, Fuzzy mushrooms
3 leathers
2 med-large frogspawn
2 head branching hammer
ORA green birdsnest
acan
Zoa colonies, 3 large, 3 small
tri-color valida
blue, green, tri-color Florida Ric
Kryptonite Candy Cane
Trumpet Coral (big)
7-head Dendro
War Coral
Red Caps (6-8 spread out)
Rose Millepora (2 small)
Green Star Polyp
Anemone

 

[mr_X]

all those stonies are fairly small. i kept much larger colonies than that in my 195 with just water changes for a couple years. i have heard of tanks using much more alk than ca also, and i think it's more common than the other way around (unless of course we're talking mature sps reefs).

 

[mr_X]

btw, BRS or gettanked aquariums to save a couple bucks on bulk additives.

 

[Idaho-Tank]

I have consistently had to add buffer to bring my KH up to 9. The salt I use (oceanic) seems to have very high Ca and thus I have not had to add any. It has dropped however over the past two months from the 480 range down to the 420-440 range. I assume it has something to do with the additional coral Ive added?

I do a 10% PWC per week.

I have been testing my alk once a week... not every other day like you... makes me wonder if it is dropping fast like yours does. Mine will drop to 7-8 in a weeks time. Perhaps I should be monitoring that closer.

 

[mr_X]

straight oceanic would leave me with an alk of around 6.

 

[Floyd R Turbo]

Instant Ocean Reef Crystals mixed up to a salinity of 35 gives Alk 14 Ca 420 Mg 1170. That's 3 cups per 5 gallons (0.5 c/g = sal 28-29)

Yeah I was wondering how big the colonies had to get before really starting to suck the calcium down. That might explain it. I guess I was wondering if there was a reason why the Alk would drop and not the Ca, and maybe that having to do with Mg level or Stront. I haven't messed with those, but I've heard 400-450 Ca 8-12 dKH 1500 Mg (?) and what like 6-9 Strontium?

BTW Salifert Strontium is a pain. But at least you verify that your calcium kit is right halfway through the process.

 

[mr_X]

i don't know the why's of it, but i do know that you will use alk. it's not just there to oppose calcium.
a friend of mine kills a ton of sps with alk swings. he runs a reactor and can't seem to get the alk to stay in a decent range for long. i told him to get rid of the reactor and just start a 2 part drip. BRS sells those dual dosing pumps that you can dial in perfect. and as the coral load grows, you just crank up the pumps a notch. seems a lot easier to me.

i must have had an angel watching over my tanks. you folks test a lot more than i do. i just did my weekly water changes and didn't whip out the test kits unless i saw a widespread problem....and i never did.
i didn't test the water on this tank for over a year:

 

[Floyd R Turbo]

Still dropping daily

11/3: KH = 7.7-7.8. Added 5g KH Buffer. Topped off 2 gal RO
That should have boosted it to between 8.7 and 9.1, but I topped off also.

Next day (today)

11/4: KH = 8.0. Added 5g KH Buffer. Did not top off.

I'll test it tomorrow before I top it off for the weekend. I'm trying to get a handle on rate of evap, so I can figure a daily dose to put in the top off water. That may change when I add a glass top to the sump though. I wouldn't do it if I could, but they have a condensation problem with the hinges and more importantly the metal square beams that run the length of the tank at the front and back in the cabinet. The last sump was a pretty bad arrangement and there was salty evap adhered everywhere in the sump cabinet.

 

[mr_X]

why not just start a sodium bicarb drip? top off that way.

 

[Floyd R Turbo]

You mean Baking Soda, right? I suppose that would be a lot cheaper. I don't have time to look it up, but isn't there something about putting baking soda in the oven at a certain temp for a certain amount of time? I seem to remember reading that if you add it right out of the box, it tends to lower pH and heating it causes it to actually raise the pH.

 

[mr_X]

yeah, you are supposed to cook it. i am not sure of the exact procedure. i just use the BRS or gettanked stuff if i have a crazy coral load. it's not that much more expensive than a box of arm and hammer really. i think 8 pounds is like 16 bucks. 8 pounds will last you a bit.

 

[Floyd R Turbo]

No kidding!!! I'll have to keep that in mind when I run out of the Brightwell stuff. Just cracked a new jar. Was thinking I should get the 2-part or 3-part ca/alk/mg from BRS their video tutorial was pretty good. Something for down the line when the levels are dropping daily and consistently.

 

[Innovator]

Here you go, read up

Reef Chemistry Articles - Reef Central Online Community Archives

 

[mr_X]

check out gettanked too. he's real cheap. he lives fairly close to me and made a trip out here before when i had my coral system running. he dropped off a bunch of samples to hand out to my customers and gave me a ton of salt mix to try. nice guy and eager to help out.

 

[cmor1701d]

OK, Baking soda is Sodium BiCarbonate. Use that when pH is high (8.4). Use Sodium Carbonate when pH is low. To turn Baking Soda into Sodium Carbonate, spread 2 ¼ cups on a baking sheet (I cover the sheet with aluminum foil) and bake at 300 for an hour. I bake it at 350 for 1 - 2 hours. That will make a gallon of Sodium Carbonate.
That is right from Rand'y two part formula.

I'm dosing about 1½ Alk to Ca, though I think my Ca depletion is now catching up.

I'm about ready to get a dual dosing pump, or two if I can't adjust the dual separately.