Low Calcium but Perfect Alk in SPS tank

[wolffman1992]

So for the past two days it has come to my attention that my calcium levels are rather low around 320ppm. My alk is at 4/meq/L which is where I like it. My Mag levels are around 1350. I am currently using AQI saltwater test kit for the calcium. The kit itself is about a year old and I am wondering if the chemicals in the kit are dated and giving me an inaccurate reading. Typcially Alk depletes much faster than calcium in my experience and I have been adding calcium and alk daily. My tank is an SPS dominated tank with several large colonies. Any thoughts guys and girls? Have you ever experienced this? I use Red Sea Pro Salt and do a 15% water change every two weeks. Old test kit or does something need correcting?

 

[reefstarter]

I would get confirmation before going nuts but to be safe maybe add a very small amount of calcium more to keep it stable and not drop further

 

[wolffman1992]

Yeah I added some this morning going to test back tonight and see what the new levels are. I typically use Kent marines liquid solution and also there carbonate liquid solution. I typically add 1 to 2 milliliter a day so I doubled it to see what that gives me.

 

[PSU4ME]

I would figure out what a 20ppm increase is for your water volume.....dose that and then test to see if your kit registers it........it might be your test kit

 

[wolffman1992]

That's a good idea thank you I will research that and figure that out

 

[nemodan]

If your corals looks healthy as always I will not change anything until you reconfirm the results. Just my though based on past experiences with a similar issue.

 

[wolffman1992]

Now idk if this calculator is correct but the reef calculator which allows you to pick the products name brand you are dosing with said that I would need about 348ml of Kents marine liquid calcium to raise from 320ppm to 450. Kents marine liquid calcium is 10% calcium or 100,000 ppm is this a weak product ? I've used it for over 6 to 7 months now with geat results and levels until recently.

 

[wolffman1992]

There is no way that can be correct right?

 

[wolffman1992]

I am going to mix up a batch of Red Sea pro salt and see if my test reads between 390 to 450 and see if my test is off

 

[wolffman1992]

That test is accurate my test came in at 420 on the freshly mixed batch of Red Sea pro. Might have to go with a powdered form of calcium

 

[daves-reef]

If your corals looks healthy as always I will not change anything until you reconfirm the results. .

I agree 100%, I have come to always suspect test kit accuracy and learned the hard way never chase numbers. Stability over a specific value is all I look for now. As long as your in recommended range.

I would get a new test kit or maybe two that are different brands. I never found two test kits give the same number. Having an LFS check your water is a good idea too. I even went the online route once but not sure the value there. I do recommend getting a new test kit before the old runs out so you can compare results from same sample. You rarely if ever get identical results IMHO. Never between different manufactures in my experience. If your corals look good and nothing changed like how you supplement. Just shoot for stable number in range not a specific number.

 

[reefkeeper2]

That test is accurate my test came in at 420 on the freshly mixed batch of Red Sea pro. Might have to go with a powdered form of calcium

Adding calcium chloride (powdered calcium) will bring your calcium up, but will lower your Alk. Whatever you do, go very slow with it and check your Alk often. You don't want your Alk bouncing around with large sps colonies at stake.

 

[delta]

your ALK is over 11DKH @ 4meg/l so once CA goes below a certain point probably 440-450 your ALk is pushing it down. you need to balance the trifactor. Ca, Alk and Mg
So if you are going to run your alk at 11+Dkh your CA and Mg need to be higher and you will battle keeping your Ca up