Is this calcium usage within acceptable ranges?

[shollis2814]

36 gallon tank with 4-6 gallon sump (I'm calling it 40 gallons for ease of dosing).

ph 8.2
Salinity 1.025
Kh 10-11 (Using API. It starts a color change at 10 but goes all the way at 11, so 10.5?)
Magnesium 1350
Calcium is hovering around 380. I am using Seachem to dose, either Reef Complete or Calcium only depending on Magnesium. Using API Calcium test. I know it's not the best, but I want to use it up before I buy a different kit.

The directions on Reef Complete say that I can use 5 ml/80 l (20 gallons) but not to exceed 12.5 ml/80 l. With my 40 gallon I am putting 20-25 ml every day or so. I am not dosing kalk yet, because I read I should get my levels up before dosing and use Kalk to maintain.

I mostly have LPS: zoas, frogspawn, duncans, blastos. In the SPS world (I think, I'm still learning which goes where)I have two small favia frags, a catspaw, a small Cyphastrea frag, a small Superman Montipora frag, and a large Hollywood Stunner. I do have coralline algae on rocks, but not on my glass.

Does this sound 'normal'?

 

[Prozack199]

I Keep My Calcium Around 400-425
So You Could Raise It, But Not Sure How Accurate Api test Kits Are.

 

[shollis2814]

I am trying to raise it, but I am hitting the max dose and leveling out at 380 or so. I get it up to 410 for a day and then it's back down. The LFS confirms the levels I am testing out, but they could be using API, too.

 

[Prozack199]

Understanding You Want To Use That Test Kit Befor Getting Something Else. But Id Get a Salifert Test Kit Or Red Sea To Double Check Where Your At And Maybe Switch To a Two Part Dose Like B-ionic.
What Kind of Salt Your Using Just Curious?

 

[shollis2814]

Understanding You Want To Use That Test Kit Befor Getting Something Else. But Id Get a Salifert Test Kit Or Red Sea To Double Check Where Your At And Maybe Switch To a Two Part Dose Like B-ionic.
What Kind of Salt Your Using Just Curious?

I don't have an RODI unit yet, so I am using LFS water. It's the same stuff they use in their display tanks. Calcium tests 410-420 in the jug.

 

[Randy Holmes-Farley]

20 mL of Reef Complete is adding about 20 ppm of calcium. That would be matched by about 1.4 dKH of alkalinity demand.

It is not excessive. If it is dosing more than you need to match demand, it may take a while to detect it against normal kit variations, and it may also be offsetting drops in calcium from water changes with a low calcium mix.

 

[shollis2814]

@Randy Holmes-Farley Thanks. I have switched to a dissolvable powder for boosting and will go back to liquid dosing once I raise levels to above 400.

The day after that dosing, I noticed my alkalinity had gone *up* almost exactly 1.5 from 10.5 to 12 and my Magnesium had dropped from 1300 to 1150.

 

[Randy Holmes-Farley]

@Randy Holmes-Farley Thanks. I have switched to a dissolvable powder for boosting and will go back to liquid dosing once I raise levels to above 400.

The day after that dosing, I noticed my alkalinity had gone *up* almost exactly 1.5 from 10.5 to 12 and my Magnesium had dropped from 1300 to 1150.

The magnesium result is testing error, unless you did a massive water change with a low magnesium mix. Real magneisum depletion is going to be much less than 1 ppm per day unless the alk demand is very high.

 

[shollis2814]

I will recheck, but I took all my test values into my LFS with a sample of water and they confirmed the same results. There was no water change prior to testing.
Again, not doubting you, at all!
I don't know what would be having such a high alk demand in my tank. I will check Mg again today.

 

[Randy Holmes-Farley]

I will recheck, but I took all my test values into my LFS with a sample of water and they confirmed the same results. There was no water change prior to testing.
Again, not doubting you, at all!
I don't know what would be having such a high alk demand in my tank. I will check Mg again today.

FWIW, many people get erroneous magnesium results. There is just no way for it to drop more than a couple of ppm in a day. :)

 

[shollis2814]

As an experiment, I took in another sample to my LFS and just asked for alkalinity, calcium and magnesium to be checked.
The results were different than yesterday. I told this guy (one of the managers) about the results yesterday and that I had done nothing to the tank in the last 24 hours. He basically said the calcium color change on their kit was kind of subtle and told me to let him check it for the next couple of times.

 

[Randy Holmes-Farley]

That's an unfortunately too common experience: test results are often not as accurate as we would like.

 

[shollis2814]

@Randy Holmes-Farley as an update, I discovered today that it was my *calcium* test kit that had gone bad and was giving me a reading of 340, when it was really more like 420-440. Things are stabilizing!

 

[Randy Holmes-Farley]

Sounds good!

Happy Reefing. :)

 

[TCFletch]

So if test kits don't work then why are we buying them and supporting the companies that make them? Better to just look at your livestock. If they're thriving then you can assume that your water perimeters are where they should be and so you can keep doing what you're doing. Otherwise it's just trial and error. We all know nothing good ever happens fast in this hobby. Trial, error and a lot of patience.

 

[Randy Holmes-Farley]

Many kits work fine, and some do not. Many work well enough to get a handle on what is happening, as long as you accept there is a significant variation in them.

For example, calcium is fine in a reef at, say, 380-550 ppm. If a kit says 440 ppm, you are almost certainly fine.

If it says 440 ppm one day and 460 ppm the next, that does not, IMO, necessarily mean the calcium rose by 20 ppm. :)