Low Calcium

mombostic

Member
My calcium is testing at around 320. Isn't that a little low? My alkalinity is 3.5 and the PH is 8.3. I have some "Liquid Reactor" stuff, but it also raises PH. What causes low calcium? I thought regular water changes should keep levels like they should be.
 

ifirefight

Active Member
https://forums.saltwaterfish.com/t/175205/calcium-alkalinity-chart This is a "balanced" chart. If your alk is 3.5 then your calcium should be......430. These are just numbers to shoot for,not "the law of the land". You can adjust levels by water changes,or slowly drip a calcium additive in your top off water. I cant be more specific since you have not mentioned tank size,last water change,corals,fish,etc..etc..etc..the amount of corals will affect the calcium level in your tank.
 

mombostic

Member
Since my alk is normal, don't I need to be careful adding something to raise the calcium? The liquid reactor stuff says it raises PH, but my PH is normal.
Here's the info:
75 gallons
10 gallon water change every Sunday, Instant Ocean salt
35 salinity
0 amm
0 nitrites
<10 nitrates
0 phosphates
3.5 alk
320 calcium
8.3 ph
1 Bubble tip
2 percs
1 royal gramma
1 female lyretail anthias
1 sixline wrasse
1 coral beauty
1 colt
1 toadstool looking softy
sun polyps
deep sea yellow gorgonian
small ricordia colony with one mushroom attached to rock
5 new very small frags--montiporias and acroporas
 

ifirefight

Active Member
If you are doing a 10 gallon water change every week in a 75 gallon tank...that may be enough to keep levels in check. I have heard different opinions on Instant Ocean salt though. I am unfamilar with "Liquid Reactor" so I cant address that. But like I said before..If your water changes are not keeping your calcium levels where you like ..than you need to drip an additive. Some people use Kents liquid calcium, but there are lots of brands to chose from. Also ..make sure you are using a "good" test kit. Sometimes people get "false readings" with the "cheaper" test kits.
 

bonebrake

Active Member
Your pH is relatively high, which is a good thing; I consider 8.3-8.5 perfect pH. This increases the use of calcium in both biotic and abiotic calcification, but given your water change schedule and the amount you change there is no way it is being used up this fast. Your sea salt mix has to be deficient in calcium.
Your solution would be to switch to a different sea salt that is formulated for reef tanks and mixed with RO/DI or supplement your current sea salt with a calcium chloride solution.
I have the exact same problem: I use Red Sea Salt and when freshly mixed to 35 ppt, 1.026 s.g. at 78 *F calcium is only ~300 ppm. I bump it up to 420-450 ppm using Seachem's Reef Complete.
It is pure calcium chloride which will not have any effect on your pH.
I have a total volume of 30 gal. and I change 25% every ~14 days and a bottle lasts me a little over six months. You'll use more, but it is cheap and well worth the improvement you'll see in your stony coral and coralline algae growth. At the calcium concentration you are at now, your stony coral and coralline algae growth is being held back to a crawl if not completely stopped.
:joy:
 

mombostic

Member
Awesome information.
I didn't see how it could be used that fast, either, but I never had the sense to test the calcium level of my new water while it was waiting in the plastic tub to be changed. I will do that Sunday morning before my water change and see what's going on.
Can't the addition of calcium have a negative effect on the alkalinity reading? Alkalinity is also important in the growth of stony corals, right? On a side note, I was a biology major with an English minor, and this chemistry crap SUCKS!
 

bonebrake

Active Member
:
Originally Posted by Mombostic
Can't the addition of calcium have a negative effect on the alkalinity reading? Alkalinity is also important in the growth of stony corals, right? On a side note, I was a biology major with an English minor, and this chemistry crap SUCKS!

Yes and no: without getting complicated, as long as your calcium is 400-450 ppm and your alkalinity is 2.5-4.5 meq/L and your pH is 8.0-8.5 don't worry about it!

Consistency in these ranges is the most important: you don't want to be bouncing all over the place on a daily basis, that would have negative effects for sure.
:joy:
 

mombostic

Member
I tested my clean water this morning and it tested around 360. That's a little higher but still not up to par. So now I'll try the Sea Chem. You're adding that to the clean water BEFORE the change, right?
 

azfishgal

Active Member
I have to add liquid calcium every day to keep my calcium between 400-450, and then I add the Kent Marine Superbuffer-dKH to keep the pH and alk up, but I don't have to add the buffer every day. For my tank (125 gallon) once I got the calcium where it needed to be (400-450) it's been very easy to keep it there by adding 2 tsp of liquid calcium every day (I add it when I do my top off in the morning). But keeping my pH and alk where it needs to be has been a bit tougher, but I'm getting the hang of it. It's starting to look like if I add my buffer every two days the pH and alk stays balanced. I also check my fresh saltwater mix to be sure the calcium, pH, and alk are the same (as well as the salinity of course). I to was confused on this whole balancing act, but now it's getting easier and I'm happy to report my purple coraline is starting to spread.

Oh, after I use up my liquid calcium I'm switching to turbo calcium, more cost effective.

Edit: One more tip, if you add both calcium and a buffer, be sure to add one in the morning and one at night.
 

bonebrake

Active Member
Originally Posted by Mombostic
I tested my clean water this morning and it tested around 360. That's a little higher but still not up to par. So now I'll try the Sea Chem. You're adding that to the clean water BEFORE the change, right?
Yes, I add everything in the bucket before the change.
:joy:
 

a sea k

Member
If the salt brand your using is deficient in calcium, it is probably deficient in magnesium as well. If this is the case you will have a hard time raising calcium levels. Test your magnesium and adjust before trying to boost your calcium.
I agree with Bonebreak's suggestions as well, good advice.
 

cgj

Member
I have a very hard time getting my calcium above 400ppm... is it ok to raise that rapidly, by say, dosing extra liquid calcium (kents)? So if I were to go from 400ppm to 420 or 440 ppm in a day, is that alright.
 

azfishgal

Active Member
Originally Posted by CGJ
Someone chime in? Is it safe to raise calcium rapidly?
Going from 400-450 in 24 hours is ok IMO. I actually went from 350-420 in two days with no ill effects. I dosed once in the morning, once at noon, and once at night. I think it's more important to get your tank where it needs to be. Now this is just with calcium, I wouldn't do this with the pH.
 

sjimmyh

Member
Instant Ocean is a little low in the Calcium Dept. Fresh buckets at 1.022 SG tended to yield around 360 ppm for me mixed with RO/DI water. Many brands are now out that are designed for reef systems with higher calcium levels. Instant Ocean makes Reef Crystals, which does have higher Ca. Oceanic tested around 480 ppm for me.
Raising Calcium itself shouldn't really be an issue. Its how it will affect your pH and Alkalinity that I would worry about more. As long as these don't change too much for your additions it shouldn't have much effect on your livestock.
 
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