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Rhodesholar
09/11/2015, 07:49 PM
Can some one help me here.

My Magnesium is 1289. Alk is 9. I add calcium supplement and the calcium goes down, not up. Currently at 380 and can't raise. Any one have any ideas as to what is going on?

bertoni
09/11/2015, 08:12 PM
What supplement are you using, and how much are you adding. How big is the tank?

Rhodesholar
09/11/2015, 08:32 PM
The tank is about 80 gallons. I am adding BRS Calcium chloride. I am adding about 3 oz at a time once a day.

bertoni
09/11/2015, 09:01 PM
Assuming you're using the liquid solution, that's about 20 ppm per day, assuming about 50 gallons of water in the system. The tank might be consume that much per day, and it's fairly close to the noise limits in our kits. I'd try doubling the dose, to see what happens, and then doubling again. It should be safe to raise the calcium by 100 ppm per day or so.

How long after adding the calcium are you waiting to measure the result?

Rhodesholar
09/11/2015, 09:12 PM
Assuming you're using the liquid solution, that's about 20 ppm per day, assuming about 50 gallons of water in the system. The tank might be consume that much per day, and it's fairly close to the noise limits in our kits. I'd try doubling the dose, to see what happens, and then doubling again. It should be safe to raise the calcium by 100 ppm per day or so.

How long after adding the calcium are you waiting to measure the result?

I wait anywhere from 2 hours to 24

bertoni
09/11/2015, 09:29 PM
2 hours should be plenty of time. 24 hours is fairly long. My tanks could consume 20 ppm of calcium in about that time, maybe a bit less. 10 minutes likely is more than long enough to wait.

Rhodesholar
09/12/2015, 02:02 PM
The tank is very lightly stocked. I have two small acropora frags and ALOT of coralline algae but that is it. I can't see the tank sucking up as much calcium as I am adding.

bertoni
09/12/2015, 09:26 PM
Coralline algae regular consumed 20 ppm per day and probably even more in my soft coral tanks. I was dosing 3 dKH in 2-part and running with saturated limewater, although the evaporation rate was low.

downbeach
09/13/2015, 04:13 AM
It would be odd if you had to dose Ca before adding any Alk supplement. Are you using any type of pH buffer? Using tap water to make your SW and top off? If the tank has an uptake of ~20ppm Ca per day, you should see an Alk consumption of about ~3dKH per day, even if you consider some abiotic precipitation. What test kit(s) are you using? How about your salt mix, and are you doing any WC's between your tests?

Rhodesholar
09/13/2015, 11:46 AM
Thank you for the replies to this issue.

I am not dosing any PH buffer. I add 1.5oz of Randys alk recipe 2 once a day for the ALK. I like to keep my alk around 9.

All water for both top off and water changes is RO that measures 0 for TDS.

I am a testing junky and will test several times a day for CA levels and maybe once a day for alk as that seems pretty stable. No water changes in between testings for CA. I use Instant Ocean or Reef Crystals for my salt mix. I change 20% once a month.

Test kits are API that have always been accurate in the past and don't expire until 2016.

Rhodesholar
09/17/2015, 01:57 PM
Tried upping the dose. Calcium went down from 380 to360,

If anyone has any ideas that would be great.

Staisman
09/17/2015, 02:26 PM
According to the calculator on BRS website with 50 g of water you need to add
Need: 460.5 ml
or 15.5 fl oz
or 92.1 tsp
That's to rise calcium from 360 ppm to 450 ppm. I think your dose is too low.

See your self here http://www.bulkreefsupply.com/reef-calculator

Rhodesholar
09/17/2015, 02:59 PM
Ok let me explain.

1. Test calcium - 380
2. Add Brs calcium chloride mixed to directions
3oz or maybe 4oz to 80gallons of water

3. Test maybe 10 minutes later as recommended earlier

4. Calcium now 360 and does not go up

Staisman
09/17/2015, 04:31 PM
Take a water sample and go to the local LFS and let them test it with something more reliable like Salifert or Red Sea. Or just buy a test for calcium and check with different test kit.

bertoni
09/17/2015, 07:52 PM
Assuming 80 gallons of water volume, I get 8 fl oz to raise the calcium by 30 ppm. 30 ppm is getting close to the resolution limits of our kits. I'd try 8 fl oz, wait 15 minutes, and try 8 more oz, and see what happens.

Rhodesholar
09/17/2015, 08:32 PM
Ok. I will try that. My concern here is that I don't want to crash anything.

bertoni
09/17/2015, 09:19 PM
You should be fine. If you're very worried, you could try measuring between the 8 fl oz doses.

Rhodesholar
09/17/2015, 09:24 PM
Thank you Jonathan.

I will give that a try. Perhaps I am just being to cautious.

outssider
09/18/2015, 05:42 PM
using the api test kit for calcium there is only one drop difference between 360 and 380ppm ...you really need a more precise test kit.....

Rhodesholar
09/18/2015, 07:42 PM
Solved. Testing kit error. Got a new test kit. Calcium reading 420 which is where my dosing should be.

Thank you to all who responded to this thread.

bertoni
09/18/2015, 08:10 PM
Okay, that makes sense. :) Unfortunately, testing errors are fairly common.