shrinking alkalinity.....high calcium

[kyles]

Randy, I got a bit of a problem.....my tank parameters are:

Ph 8.0 night and day -salifert
SG 1.025 (using Oceanic salt)
Nitrites -undetected -red sea
Nitrates -undetected -red sea
CA over 500 ppm - salifert
Alk 7.0 dkh -salifert

My tank has been set up for over 3 years now. 55 gal w/ about 25 gal fuge w/ DSB.
I drip Kalk (Balls pickling lime) every day/night.....about 3 tsp per gal. And it uses about 1/2 gal per day.
It is a mixed reef with mostly LPS, a few SPS, and now recently some soft (Xenia's Growing Like weeds)
My tank is covered but my fuge is always open with a fan circulating air in the stand.
No new live rock or anything other than Xenia
All my corals are growing good.


I do a partial H2O (ro/di) change every week, 4 gals, using Oceanic....used to use instant ocean.

I used to test my parameters every few days to a week and they were always so steady. CA 400, Alk 9.0, PH 8.0

Here is where it gets interesting......2 weeks ago I tested my parameters.... CA over 500, Alk 6.7, PH 8.0

So I tried to raise my Alk to about 10 dKH. 3 tsp of baking soda over 3 days (1 tsp per day).
I tested it on the third day about 1 hour after the last baking soda treatment..... CA over 500, Alk 10.2, PH 8.6 (sh..t)
Yes I was worried that the 1 tsp of baking soda caused such a spike in PH. I tested again, and again, same thing.
Then I tested the next day, and all was fine CA over 500, Alk 10.2, PH 8.0....Hurray!

Now here is where it gets weird,
I tested it again 5 days later and my readings were:
CA over 500, Alk 7.0, PH 8.0
My question is this, why is my Alk dropping so rapidly? And Why is my CA so high?
Am I adding too many tsp of kalk in my make up water, 3 tsp?
What is consuming my Alk so fast? and Not my CA.

[Sloth]

I'll take a stab -

When you say calcium over 500 mg/L, does that mean its off the chart? Where is it exactly? If its off the chart, it could be well over 500 and might actually be dropping at a normal rate.

IME - alk levels drop faster than calcium levels. Have you been adding any calcium chloride or anything other than kalk for calcium? Somehow, I think you need to stop adding as much calcium and concentrate on keeping your alkalinity up with baking soda. Once your calcium drops to a normal level, I think it will be even easier to keep your alk more stable.

[kyles]

yes, it's off the chart.
so then I should regularly add some baking soda? Is it safe to do so on a maitenance basis? What's causing my problem?

[kyles]

no, not adding anything other than kalk

[Sloth]

Too much calcium can be a very bad thing. Not sure why your calcium isnt dropping along with your alk. Maybe you just started out with high calcium from day one. Or maybe your high calcium is causing your alk to drop out of solution and precipitate on heaters and pumps.

I'd say stop adding kalk and let your calcium come down to normal levels (while using baking soda to keep alk stable). Once calcium is normal, re-evaluate what affect the kalk has on your tank. Test often. If it jumps back up, you might need to add less kalk and keep using baking soda to keep alk constant.

Whatever you do, don't add anything else that increases your calcium levels until you get an accurate reading. Just do whatever you can to get your levels normal and then go from there.

Adding baking soda on a regular basis will not harm your tank. I've been adding a teaspoon a day to my 25 gallon for a year. Just make sure you keep up with your regular water changes too.

[Sloth]

Come to think of it....
maybe I can't keep my own parameters stable because I've been using baking soda. Hehhe. Take my advice with a grain of salt.

The stuff is reef-safe even in the long run.. Thats for sure.

[Randy Holmes-Farley]

IME - alk levels drop faster than calcium levels

Yes, that's what should happen. A 20 ppm drop in calcium is balanced by a 1 meq/L (20 dKH) drop in alkalinity.

I'd get a real calcium measurement. Use a second syring, if necessary. Then add the results together.

Continue the limewater, and also add some baking soda, or baked baking soda since the pH is low. Dissolve it in some freshwater first. Add a teaspoon per day until the calciuum drops below 500 ppm.

It may be that the limewater is just not adequately meeting the demand, and so you need some additional supplements of some sort, or possibly more limewtaer if that is possible (or more lime plus vinegar).

[kyles]

I used to add the vinegar too, but I got some clumping in my DSB that I attributed to the vinegar. I actually read an article that says to dissolve the kalk in vinegar first, then add in the RO/DI water

[kyles]

Thanks Sloth and Randy.

It may be that the limewater is just not adequately meeting the demand, and so you need some additional supplements of some sort, or possibly more limewtaer if that is possible (or more lime plus vinegar).

Randy, Wouldn't more limewater make my calcium / alkalinity disparity even worse?

[Randy Holmes-Farley]

I actually read an article that says to dissolve the kalk in vinegar first, then add in the RO/DI water

Despite what some folks claim, the order of mixing of vinegar, lime, and water makes no difference.

Wouldn't more limewater make my calcium / alkalinity disparity even worse?

Disparity? You mean the high calcium? Limewater will supply both calcium and alkalinity in the same ratio that they are consumed. So once you reduce the calcium, if you then add enough of a balanced additive like limewater, you should be all set.

[kyles]

Limewater will supply both calcium and alkalinity in the same ratio that they are consumed. So once you reduce the calcium, if you then add enough of a balanced additive like limewater, you should be all set.

Well that's what I used to think, that limewater is balanced in alk and CA. And Limewater is ALL I have been adding for the past 2 years, but until recently, my alkalinity has been dropping fast, while my Ca is at the top of the chart.
What I'd like to know is what could be causing this? Will certain corals use a bunch of Alk? Do corals consume Alk & CA in the same ratio as limewater adds it? Is it Xenia, or Montipora......where is the Alk going?
Is it possible as sloth says ....
"Or maybe your high calcium is causing your alk to drop out of solution and precipitate on heaters and pumps
It would make some sense to me if because CA is so high, my alk just drops out.....hmmm, no wonder my hair algae has been growing again. Does Chaeto play a role in consuming alk too? I have some in my fuge..

[Hobster]

kyles,

In readin your thread, you stated:
"I do a partial H2O (ro/di) change every week, 4 gals, using Oceanic....used to use instant ocean"

When did you start using Oceanic? From what I have been reading it seems this salt is very high in Ca. Much higher than IO. When I tested my IO it was only around 300 or so in Ca and very low in Mg.

Just thought maybe this might have something to do with your high Ca and low ALk.

[Sloth]

nice catch, Hobster

[gtrestoration]

I have been using Oceanic and my calcium levels jump after and water change. 20 gallons in a 200 gallon system. Thats ok, but the alk is low, everytime I've tested it Salifert reads it at 2.5 meq/L. I push for over 3.25 or so. I now add 1 teaspoon baking soda and 1 teaspoon backed baking soda to the 20 gallon mixture. That takes the alk a little higher than the tank, but leaves the pH just about right.

Steve U

[Randy Holmes-Farley]

Well that's what I used to think, that limewater is balanced in alk and CA.

It is still true.

There are some things that cause slow drifts in calcium and alkalinity, but a quick drop in alk is not an indication of them.

I suspect that you are mostly seeing a math thing. If you start at 550 ppm calcium and 4 meq/L (11 dKH) alkalinity, you could drop all of the alkallinity (to zero dKH) via calcium carbonate precipitation, and the calcium would still be 470 ppm. Calcium just doesn't miove as rapidly.

Chaetomorpha has essentially no impact on alkalinity.

All corals as well as abiotic precipitation on heaters uses 20 ppm calcium for every 1 meq/L (2.8 dKH) of alkalinity (ignoring that some magnesium also gets into the CaCO3).

Water changes, the incorporation of magneisum and strontium, calcium and alkalinity in top off water and foods, and the nitrogen cycle can all slowly skew the normal values when using a balanced additivge, and ocassional corrections will be necessary.

[crpeck]

I would double check your Calcium with another test kit. I just bought a new Ca test kit from Salifert that is giving me between 50 - 100 more than it should using a reference solution. I've always had good luck with Salifert, but something is wrong here. When I test the reference solution using a Seachem test, I'm right on. I've done the Salifert 3 or 4 times on the reference solution to double check myself and its off by the same amount every time.

If you try a different Ca test, I'd be interested to hear what you get. I'm trying to figure out if I've got a bad Salifert batch or if I'm doing something wrong.

Good Luck!
Cathy

[datman422]

great thread, tagging along for I am in the same boat currently.

[cagri]

same has been happening to me since I switched to oceanic, it has high calcium 450+ and low alk, if I try to raise alk in the new make up water by more than 1mq/l by adding baking soda first then it snows(I guess because you can't have both high alk and calcium, one has to give), and then both calcium and alk drops.

It is difficult to maintain the balance with Ocenic(if you have alot of corals) because of its high calcium content. So I let the calcium slowly drop to 400 - 420ppm range while maintaining alk around 3 by adding baking soda and little kalk, and once I get there, I keep it at that level by adding more kalk.

[Randy Holmes-Farley]

Cathy:

If you try a different Ca test, I'd be interested to hear what you get. I'm trying to figure out if I've got a bad Salifert batch or if I'm doing something wrong.

I'd suggest asking Habib about this in the Salifert forum at RC. Perhaps the Salifert kit is off, you aren't using it quite right, or the standard is off.

Cagri:

e has been happening to me since I switched to oceanic, it has high calcium 450+ and low alk, if I try to raise alk in the new make up water by more than 1mq/l by adding baking soda first then it snows

How low is the alkalinity? Do you have an actual value for calcium in that batch? Adding 1 meq/l with actual baking soda should usually cause a problem. How much bakinng soda did you use and how did you add it?

[crpeck]

Thanks, Randy

After doing a search, I've found at least 3 other people posting about unusually high Ca with Salifert tests. Just checked out Habib's forum and there's 2 more saying they're getting higher readings off of their new Salifert kits than their old ones side by side.

I'll post over there and hopefully can get it figured out. I've double and triple checked myself and I'm sure I'm following the directions.

Thanks!
Cathy

[RQ]

I have the same problem with alk. I tried to rise it with baking soda, and obtained the same results as kyle. At first the alk rose and after a week returned to previous levels.
I m still searching for the solution.

[Randy Holmes-Farley]

At first the alk rose and after a week returned to previous levels.

Are you talking about in an aquarium, or a bucket of artificial salt water?

[cagri]

Randy,

I mixed 40 - 45 gallons of oceanic salt. Results were 480 ppm Calcium and 2.5 - 3mq/l alk at 35ppm salinity, so I decided to push the alk higher by adding kent's alk suplement(reef builder), I calculated that if I added 2 teaspoons it would raised the alk by 1 mq/l, when I did that it started snowing , and then all levels dropt. Calcium dropped to 350ppm, and alk was like 2.0 mq/l.

If I add the mixed oceanic salt with 480 calcium and 2.5 alk into my tank first , and then supplement it with alk for couple of days to maintain 2.5 - 3 level, and let the calcium drop to 400 - 420 level, and then supplement it with full power kalk mix, all is well.

I just found out that it is very difficult to maintain alk when calcium is very high ( > 450 ) with just kalk, once calcium drops to 400 level, it seems it is much easier to maintain both with just kalk.

In 3 month I will be upgrading to calc reactor, and will see how that will work out.

[kyles]

Wow, a lot going on in this thread.
I did check my Salifert CA & ALK test against a Red Sea....they were consistent......

On Saturday, before I did my water change My test showed:
PH 8.0
CA 500
ALK 6.7 dKH (after adding 1.5 tsp of Baking Soda w/ my 4 gal water change, it jumped to 10.9)

Okay, It's Moday morning, I just checked my readings again.....
PH 7.9
CA 490
ALK 6.1 dKH (after adding another 1 tsp of B. Soda it went to 7.8)

So in just 2 days, my alk droped from 10.9 to 6.1

So it appears the CA is coming down slowly but the ALk is droping very fast in just days, yet jumps at the slightest adjustment.

I think there may be something wrong with Oceanic salt, maybe a trace mineral that screws up your alk/Ca levels? Maybe too much magneisum and strontium?

Maybe I should switch back to IO?

[Sloth]

My tank drops alk almost as fast. I use IO. But then, I did add a lot of trace elements in the beginning. If there is a problem, I think we both have it.