Calcium staying high... ?

gmastr85

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For 2 years my I have dosed my tank using kalk in my ATO, using two teaspoons per gallon. It worked pretty well and I generally had good luck with almost all my corals. I used all Salifert test kits but rarely tested because I wasn't good at it and got inconsistent results. I hated testing and I never seemed to have the time to do it every night. I even bought a doser and never used it because of the inconsistent test results.

Fast forward to about 6 weeks ago. I had a couple chalices recede on me, and I figured it was time to start getting serious about tank chemistry. My coral bioload was getting much larger and I was afraid the kalk wasn't getting the job done. Because of the poor testing results I had in the past, I purchased a Hanna Calcium and Alk tester. Which by the way are awesome. After using a couple times, I can now test both in under 5 minutes.

A month ago my Calc was high at 550, my Mag was a little low at 1150, and my Alk was extremely low at 2.25dkh. I couldn't believe it. I mixed up BRS mag and raised it to 1250. That was easy. I slowly raised Alk to 9.0 over the course of 2 weeks. I let Calcium go thinking it would come down slowly. I use Instant Ocean Reef Crystals, and I stopped dosing Kalk altogether.

So I'm wondering a couple things. For two years has my calcium been sky high, and my alk been dreadfully low? My corals were always okay, and some of my SPS grew like weeds, but not all.. some were slow growers. I religiously do a 10% water change weekly... without missing a week ever. My PH has always been completely stable between 8 and 8.2 and my tank is on a controller and the temp stays within 1 degree. So my tank has always had stability. I just think the weekly water changes were keeping it going.

Now that I've corrected Alk my tank has taken off. In the last month everything looks awesome. Its incredible the difference between using kalk and never checking levels and using 2 part and checking. I've since hooked the alk up to my doser and its stable at 9dkh. I dose 40ml of Alk daily to keep it there. But my Calcium is still high. Not that its going to hurt anything, but it comes down to about 485. Once I do a water change it is up near 550 again.

Should I skip a water change to let it come down all the way? I haven't added any calcium or kalkwasser for 6 weeks, with the exception of the weekly water change, and its still high. When I was using Kalk, I can't imagine how high I was running all this time!

Does anyone have any advice as to why my calcium is running high? Should I just let it there? My tank is doing awesome but I do want to bring the chemistry to the proper levels. I just don't like skipping water changes. Thanks for any advice!
 
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hinovak

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My calcium has always run higher than my ALK levels in what you would call the "normal levels" my ALK is always in the 9 range, and calcium always seems to be around 480-500ish. I believe it is fairly common to have one run at higher levels than the other, even when using a two part dosing. Or at least that had been my experience. My sps have always seemed pretty happy.
 

Randy Holmes-Farley

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FWIW, I've very skeptical of the 2.25 dKH in a reef aquarium. While possibly quite low, I doubt it was really that low. I've seen literally thousands of alkalinity measurements, and anything below 5 dKH usually ends up being a testing error. The coral skeletons and sand/rock would likely be beginning to slowly dissolve at that alkalinity (assuming the pH is on the low side too).

The reason calcium is high is because the salt mix is bring it in. Many salt mixes have 500+ ppm of calcium. That's not normally a problem, although coupled with long term use of limewater (kalkwasser) it isn't optimal as the calcium may actually rise above the level in the salt mix because it is supplying a tiny bit more calcium than is used, relative to the alkalinity. I wouldn't do anything about the calcium, unless you want to consider changing salt mixes to one with a bit less calcium. 500-550 ppm calcium is fine. However, dosing just the alk part of the two aprt for a while is also a fine plan.:)

The alk is not high because you are not meeting the demand for calcium and alkalinity with the limewater, and that ALWAYS shows up first as a drop in alkalinity.

If you start at 550 ppm calcum and 11 dKH (like many salt mixes), and let corals use what they need to make skeletons (with no dosing), you can end up at 5.4 dKH and 510 ppm calcium. It is just the math of what is used up.
 
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gmastr85

gmastr85

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Gotcha thanks for all your help. I know calcium above 500 isn't the end of the world, so I'm not terribly worried about it. Just wanted to make sure.

My DKH may have not been 2.25. Like I said my original tests were done with salifert test kits and were almost 2 years old and my results were always inconsistent. I changed to Hanna checkers and they are the best! I do know that alk was very low. So I slowly started adding 2 oz. per day til its was where it needed to be. Now everything is doing absolutely awesome. Never seen growth like this!

Not that kalk was bad... it was easy... but I'm never changing back again from 2 part! Once you have a ton of bioload kalk becomes much harder to use. I guess its kind of like growing out of it... thanks for all your advice!
 

Robink

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I also just got a high reading of calcium, 500, and the only thing that I've been doing differently is adding magnesium. my magnesium is about 1240-1260 right now. I've been adding it daily to bring up the magnesium level. Would this affect the calcium? should I be worried about anything? previously my calcium was 420-440 and I was having to add calcium several times a week to keep the level up. Don't make my own water at this time... get it from lfs.
all my other parameters are normal and consistent. Just the calcium went up.
 

Randy Holmes-Farley

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I also just got a high reading of calcium, 500, and the only thing that I've been doing differently is adding magnesium. my magnesium is about 1240-1260 right now. I've been adding it daily to bring up the magnesium level. Would this affect the calcium? should I be worried about anything? previously my calcium was 420-440 and I was having to add calcium several times a week to keep the level up. Don't make my own water at this time... get it from lfs.
all my other parameters are normal and consistent. Just the calcium went up.

No, boosting magnesium doesn't cause calcium to rise.

Many salt mixes have calcium above 500 ppm. I'd check the lfs water to see how high the calcium is, but 500 ppm is not a concern. :)
 

Promodcrazy

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You might try a product called Seaman No 28 it's a slow resolve block of calcium and all minerals in reef water to replenish these elements as they are depleted to keep your tank stable. I use and it keeps my tank at 500 calcium ,Alk. 12dkh ,mag.1300.... Simple just drop,in your sump and let it do it's work.
 

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