Calcium Low for unknown reason

[jlmawp]

My calcium is absurdly low and it's got me stumped. I have a 9gal. Params are:

Ammonia: 0
Nitrite: 0
Nitrate: undetectable
Phosphate: undetectable
Calcium: 250
Alk: 3.08 KH: 8.6
Mg: 1200
Salinity: 1.025
Temp: 79F

Admittedly, 2 weeks ago was the first time I had done a water change in about a month (2 gallons w/reef crystals), but when I did some level testing that day, I saw that Calcium was at about 280. Wow, low. I added 12 ml calcium (B-Ionic) over 3 days to bring it up. Now, I'm testing almost 2 weeks later after a one-gallon water change, dosed another normal 2.5ml and somehow I'm down to 250. I waited about 30 minutes before today's testing after dose/waterchange.

Both times I tested, I used both API and Salifert calcium tests, and they were consistent each time.

As far as calcium, I have a good amount of coralline on the rocks, a small acan, 2 torches, and a small duncan. No sps.

Anyone have any ideas as to how this can be? My tank has never burned through calcium like this.

[Aquageek450]

maybe a bad batch of salt? Being that the tank is so small, if you did a water change with a batch of saltwater that had low calcium it would affect the tank greatly. Test the calcium of the saltwater next time you do a water change.

[nereefpat]

I agree that it would be worth testing the Ca on a new batch of saltwater.

Also, get a second opinion on the test itself, maybe at the LFS. I don't see how Ca could be that low.

[ROB2005]

Get a Hanna Ca checker. A little more user friendly when taking readings.

[jlmawp]

Ok, so I made a fresh gallon with Reef Crystals, and Ca came in at 200 on both tests. Guess that would explain it. Never would have thought.

I have heard of bad batches before, but this seems a little unbelievable...

[jlmawp]

Ok, just made a terrifying trip to the local Petco to get a fresh bag. That place makes me sad.

I just came home and ran another test on the new batch with both API and Salifert. Both came in at over 500 (about 520 or so.)

To me, this seems high, but I'll take it compared to 200. Are they just not dependable as a consistent product anymore? The bag says the salt should come in at about 450 for 1.025 salinity. Neither of my test kits are even close to expiration, and they have both been very close to one another on every test. My only conclusion right now is that the bags of Reef Crystals apparently vary widely in composition, depending on batch. This makes sense, because I've noticed it being harder and harder to keep up with Ca levels for a little bit...probably just in the time since I bought the last bag. I just assumed the stuff I had was growing and using more calcium over time...but not THAT much more.

I'm using Ro/Di water, scooping 1/2 cup salt per gallon as per the usual. I take my salt out of the bag and put it in a plastic bin with a lid, since bags tend to be messy. Is that a non-no? It's never been an issue before this. Just trying to figure out if there is a factor I'm screwing up. Pretty sure I'm doing everything right though...

[nereefpat]

500 ppm Ca sounds pretty normal for reef crystals. Its all, Ca, and mg are all usually a little high.

Edit: alk.

[outssider]

If you call and complain, they will send you out a replacement. you will be required to send them a small sample of the inferior product.

[jlmawp]

If you call and complain, they will send you out a replacement. you will be required to send them a small sample of the inferior product.

Oh, I had no idea that was possible. I'll call them

Did a 2-gallon water change with the new salt, and I'm up to 300. I'll do the same tomorrow, and I'll be back on track.