Increasing calcium levels

[chase33]

I've added a few sps frags to my tank over the last month or so and I notice my calcium levels have decreased . The last two times I tested the readings were at 350 and I've had one reading of 320. I change about 15% (considering the water in the sump) of the water weekly. I want to get the calcium level up to around 400 or more if it won't harm the specimens. What are the different methods I could use to increase the calcium levels and how do each work? Also, how many of you add supplements to your tanks?

[ccCapt]

First off, what brand salt are you using? What you should do is test a freshly mixed batch of water and see where your calcium and alkalinity levels are at. You can then dose your new water to get the levels where they should be. I keep my ca at 420 and alk at 8 dKH.
With only a few frags, you shouldn't have too much consumption, but test your tank water and record the readings. The following day, test again and compare with the day before to see how much ca and alk is used in your tank each day.
The only thing I dose in my tank is Randy's 2 Part which keeps my ca, alk and mag where they should be.
http://reefkeeping.com/issues/2006-02/rhf/index.php

[chase33]

The salt I am using is reef crystals. Thanks for the info. I'll take that approach.

[melosu58]

Let us know what you get when you test a fresh batch and let us know what the calcium and alk reading are.

[chase33]

Fresh batch of RO/DI water with Reef Crystals salt.
Salinity = 1.024
CA = 400
Alk = 2.8ML, or 11.5 DKH, or 4.11 MEQ/L

The tank is 120g with 40g sump, and has a weekly PWC of 20g every Sunday

Salinity = 1.024
CA = 350
Alk = 5.8 ML, or 6.7 DKH, or 2.40 MEQ/L

I usually test right after the water changes and the CA is usually about 380.

[Kurt_Nelson]

Originally Posted by chase33

Fresh batch of RO/DI water with Reef Crystals salt.
Salinity = 1.024
CA = 400
Alk = 2.8ML, or 11.5 DKH, or 4.11 MEQ/L
...

That's strange - I use RC and with DI water mixed up to the same salinity I get about 360ppm Ca and 8 or 9 dKH alkalinity. What brand Ca test you using? I've gotten the same Ca reading with both API and Salifert.

[chase33]

I use salifert for all tests except for ammonia, nitrite, nitrate & PH. For those I use the API master test kit. I just retested again and still 11.5. My tank has been up and running for 5 months now. What I find more baffling is the alk in the tank is 6.7. It's normally much higher and again I usually test after a water change.

[PC]

Originally Posted by Kurt_Nelson

That's strange - I use RC and with DI water mixed up to the same salinity I get about 360ppm Ca and 8 or 9 dKH alkalinity. What brand Ca test you using? I've gotten the same Ca reading with both API and Salifert.

Will depend on source water, filtration methods used, cleanliness of test tube, even how new your filters/membrane are if using RO unit not to mention test kits (even if same brand).

Kurt, your missing an important test when trying to raise and maint alk and ca. You need to test for mg and insure it is roughly 3 x the level of ca. IE if ca = 400ppm then mg should be at least ~1200ppm. mg is kind of the molecular tie that binds, if you will. Just as a personal note I've never comprehended why people insist on keeping higher than NSW. /shrug

[melosu58]

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

[Kurt_Nelson]

Originally Posted by PC

Will depend on source water, filtration methods used, cleanliness of test tube, even how new your filters/membrane are if using RO unit not to mention test kits (even if same brand).

Kurt, your missing an important test when trying to raise and maint alk and ca. You need to test for mg and insure it is roughly 3 x the level of ca. IE if ca = 400ppm then mg should be at least ~1200ppm. mg is kind of the molecular tie that binds, if you will. Just as a personal note I've never comprehended why people insist on keeping higher than NSW. /shrug

I'm not the one trying to raise my Ca... I was just making an observation about the Ca/Alk levels for RC "out of the pail." Agree though that if someone is trying to raise their Ca levels and is having problems, check magnesium is a good thing to do.