Raising Calcium and Magnesium

[BlueWorldJeff]

I'm having problems increasing calcium and magnesium in my 180g mixed reef tank.

Currently my tank parameters are:
Ca - 380, goal is 420
Alk - 7.8, down from 8.5 2 weeks ago. goal is 8
Mag - 1200, goal is 1400
PO4 - 0, goal is less than .10, using GFO in TLF150 reactor
NO3 - 2, goal is less than 10

I use two dosing pumps to dose BRS Calcium Chloride and soda ash

I did the calculations on how much I would need to dose at once to raise my calcium and magnesium to my desired levels and its like 4 cups of each.

I am concerned that my alk levels will swing if I dose a batch of ca or mg additive at one time. Is this the best way to raise the levels? I would def wait a day between doing the ca and mg.

I have been adding one cup to the sump to see if that increases levels, but the increase is minimal.

Would doing a rather large water change be a better idea? I use IO salt.

[greengeco82]

IO salt has lower Alk and Ca, so I dont think water changes will help much. Typically you want to mix your Calcium and Magnesium into RO water, then dose that way. Instructions from BRS say to mix 5 cups of Mag chloride with 3 cups of Mag sulfate into 1 gallon of RODI water. For Calcium Chloride mix 2.5 cups in a gallon of RODI water. Here is their calculator. http://www.bulkreefsupply.com/reef-calculator
Make sure not to raise levels too fast. I'd say raise them to your target over 5 days. You can add them at the same time.

****EDIT****
Initially I thought you were adding salt straight to your sump. I re-read your post and realize you probably are not. Do make sure your test kits are not old. As mine get old they register lower numbers than are actually in the tank. The exp. date has nothing to do with it.

[BlueWorldJeff]

Originally Posted by greengeco82

IO salt has lower Alk and Ca, so I dont think water changes will help much. Typically you want to mix your Calcium and Magnesium into RO water, then dose that way. Instructions from BRS say to mix 5 cups of Mag chloride with 3 cups of Mag sulfate into 1 gallon of RODI water. For Calcium Chloride mix 2.5 cups in a gallon of RODI water. Here is their calculator. http://www.bulkreefsupply.com/reef-calculator
Make sure not to raise levels too fast. I'd say raise them to your target over 5 days. You can add them at the same time.

I have one gallon jugs with mixed calcium chloride and soda ash hooked up to my dosers. I used to dose the mag mixture (mag chloride & mag sulfate), but now I am just adding my hand when needed.

The calculator says to get calcium from 380-420 for 200 total gallons using 2 part calcium solution to use 3.46 cups (818.8 ml)

To get magnesium from 1200-1400 using the BRS magnesium mix it will take 13 cups (3225.8 ml)!

So that would be about 3/4 cup of calcium and 2.5 cups of mag every day for 5 days? Is that on top of my dosing? I use the Drew's Dosers (1.6 ml/min) with calcium dosed at 6 min 45 sec every hour for 7 hours. That is about 75 ml per day.

[Potatohead]

You want to get the levels where you want them and then your dosing should maintain those levels. You also want to make sure your water change water is at the same levels or you are going to deplete them over time. If you are using IO you will likely have to add mag and calcium to your newly mixed water, which is fine to do.

So, manually add what you need to add to get the levels where you want them and then worry about your dosing to maintain afterwards. If you need to raise calcium 40 and mag 150 - 200 I would probably do it over three days.

[greengeco82]

Your calculations are correct. It takes a lot of Mag additive to make a difference on the test results. It seems crazy, but that is the way it is. Keep your dosers running as usual, and then add your additives several times a day for a few days. With Mag, I did 1000cc in a day. I used clear airline tubing and a valve, and dripped it in by siphon over several hours.

[BlueWorldJeff]

Originally Posted by Potatohead

You want to get the levels where you want them and then your dosing should maintain those levels. You also want to make sure your water change water is at the same levels or you are going to deplete them over time. If you are using IO you will likely have to add mag and calcium to your newly mixed water, which is fine to do.

So, manually add what you need to add to get the levels where you want them and then worry about your dosing to maintain afterwards. If you need to raise calcium 40 and mag 150 - 200 I would probably do it over three days.

Looks like IO has 400 Ca, 11 Alk and 1350 Mg, that is pretty good parameters right? Is it better to get a salt mix that has values all higher than what the tank goals are so levels are replenished on a water change and dosing is just what the corals consume? Is dosing slightly more than the consumption rate from water change to water change not a good idea?

[Potatohead]

Dosing is better than doing water changes to keep up with cal/alk demand, with your consumption you would have to do a ridiculous amount of water changes to keep up.

I doubt most IO is at 1350, they probably have some batches there but it's usually more like 1200. Now with that said it is better IMO to use salt that is lower because it is far easier to move those parameters higher than to move them lower. If you buy salt with calcium at 500 and mag at 1500 there is not much you can do to lower it. It is best to use salt with parameters similar to the tank, or something lower and bring them up to match. You can use a salt with 13 dkh if you want but if you run the tank at 8, IMO it's not a good match.

[bertoni]

The new IO seems to run about 1300-1350 ppm for magnesium:

http://reefcentral.com/forums/showth...2554264&page=9

[Potatohead]

Cool, that's good news

[BlueWorldJeff]

I guess I have a question about dialing the dosing of Calcium and Alk. If I get to my desired levels, Should I wait a couple days and see the demand and then adjust calcium and alk independently? I know the ratio is 2.8dKH to 20 ppm calcium in depletion. What is the best method for adjusting the dosing pumps to match consumption?

[Potatohead]

Originally Posted by BlueWorldJeff

I guess I have a question about dialing the dosing of Calcium and Alk. If I get to my desired levels, Should I wait a couple days and see the demand and then adjust calcium and alk independently? I know the ratio is 2.8dKH to 20 ppm calcium in depletion. What is the best method for adjusting the dosing pumps to match consumption?

Typically people wait a few days. I prefer to guesstimate (on the low side), test daily and adjust the doser as necessary, this provides less of a swing usually.

[bertoni]

I would measure the alkalinity level and adjust calcium and alkalinity together until I got a good trend line. After that, you could test every few days or a week or so to tune the calcium line. The problem with measuring calcium is that our test kits are fairly imprecise. Results with 15-20 ppm or so should be considered identical, depending on the test kit.

[BlueWorldJeff]

So, my alk has been around 7.9-8.4 the past couple months

ALKALINITY
Value Date
8.34 dKH Wed April 26, 2017 06:13
8.46 dKH Tue April 25, 2017 05:57
8.34 dKH Mon April 24, 2017 16:05
7.67 dKH Mon April 17, 2017 10:28
7.9 dKH Fri April 14, 2017 12:39
8.23 dKH Mon April 10, 2017 13:47
8.12 dKH Sat April 8, 2017 17:14
8.4 dKH Mon April 3, 2017 12:07
8.46 dKH Mon March 27, 2017 11:07
8.4 dKH Fri March 24, 2017 11:11
8.51 dKH Sun March 19, 2017 15:06
8.29 dKH Sat March 4, 2017 14:38

I have stopped messing with the doser for alk, as I am trying to get my calcium up.

For calcium, I cant get it over 400. I've jacked up the doser to 75 ml per day and have been adding a cup to the sump and retested. Is the calcium precipitating out or being used? I dont think I have that much coral yet.

CALCIUM
Value Date
390 ppm Mon April 24, 2017 16:08
370 ppm Mon April 17, 2017 10:30
375 ppm Fri April 14, 2017 12:39
370 ppm Mon April 10, 2017 13:44
360 ppm Mon April 3, 2017 12:07
350 ppm Mon March 27, 2017 11:06
370 ppm Fri March 24, 2017 11:15
370 ppm Sun March 19, 2017 15:13
380 ppm Sat March 4, 2017 14:39

I'm running low on calcium chloride and it comes tomorrow. I want to dose a cup of calcium per day until I get to 420, will that swing the alk at that point?

[bertoni]

That alkalinity range is small, and I think it's stable enough for our purposes. I think the noise limits in our test kits.

Assuming you are using the recipe 1 two-part, and there's about 200 g of total water volume in the system, it'll take about a liter of supplement to raise the calcium by 50 ppm:

http://reef.diesyst.com/chemcalc/chemcalc.html

I might try dosing 500 ml as a first shot. Of course, you know more about the total water volume than I do, as well, so you might need to fix that guess.

[BlueWorldJeff]

Originally Posted by bertoni

That alkalinity range is small, and I think it's stable enough for our purposes. I think the noise limits in our test kits.

Assuming you are using the recipe 1 two-part, and there's about 200 g of total water volume in the system, it'll take about a liter of supplement to raise the calcium by 50 ppm:

http://reef.diesyst.com/chemcalc/chemcalc.html

I might try dosing 500 ml as a first shot. Of course, you know more about the total water volume than I do, as well, so you might need to fix that guess.

What are the effects on alk when dosing that much CaCl2 at once? Will I need to adjust the alk dosing because of the calcium level increase?

[bertoni]

If my guess as to the water volume is close to correct, the dose should be fine. The alkalinity level should remain the same. I would dose into the display tank, assuming that's the largest volume of water.

In theory, the alkalinity consumption might rise if corals start growing more rapidly, but that is unlikely.

[BlueWorldJeff]

Any idea why my pH is in the 8.5-8.6 range according to my Seneye? I need to recalibrate my Apex pH probe, but shouldn't Seneye be accurate? I would think it was because I had high alk and was dosing alot, but it seems in range. Could it be from all the algae on my sandbed and the photosynthesis occuring?




Also had this happen to the probe holder in my sump this past week, not sure exactly how long it was sitting in the water like this. Couldnt be more than a week

[bertoni]

The high pH might be a measurement error. Labs calibrate their pH meters every day, for example, although that's overkill for our accuracy needs. Photosynthesis can drive the pH up, but good aeration should be able to keep the level below 8.4 or so. You could check the water surface for any films, and see whether the skimmer needs a bit of cleaning or tuning. Surface films are very rare, but it's easy to check.

[BlueWorldJeff]

So I got my calcium up to 400 then 415, but then it skyrocketed to 455. I turned down the doser a little

Calcium Measurements

455 ppm Mon May 8, 2017 12:11
415 ppm Fri May 5, 2017 17:14
415 ppm Thu May 4, 2017 15:07
400 ppm Mon May 1, 2017 11:32
380 ppm Thu April 27, 2017 06:45
390 ppm Mon April 24, 2017 16:08
370 ppm Mon April 17, 2017 10:30
375 ppm Fri April 14, 2017 12:39
370 ppm Mon April 10, 2017 13:44

My alk dropped to almost 7, before I upped the doser ( this corresponded with turning down the calcium doser)

Alkalinity Measurements

7.39 dKH Mon May 8, 2017 12:08
7.39 dKH Fri May 5, 2017 17:01
7.06 dKH Thu May 4, 2017 15:04
7.78 dKH Tue May 2, 2017 06:00
7.78 dKH Mon May 1, 2017 11:29
8.18 dKH Thu April 27, 2017 06:44
8.34 dKH Wed April 26, 2017 06:13
8.46 dKH Tue April 25, 2017 05:57
8.34 dKH Mon April 24, 2017 16:05
7.67 dKH Mon April 17, 2017 10:28
7.9 dKH Fri April 14, 2017 12:39
8.23 dKH Mon April 10, 2017 13:47

Magnesium was bulk dosed to get to 1350, but has dropped. I am thinking of setting up a doser for my mag mix, but not sure if I could just manually dose when it drops out of range, or if its even necessary

Magnesium Measurements

1230 ppm Mon May 8, 2017 12:17
1275 ppm Fri May 5, 2017 17:14
1275 ppm Thu May 4, 2017 15:10
1290 ppm Mon May 1, 2017 11:36
1350 ppm Mon April 24, 2017 16:12
1200 ppm Mon April 17, 2017 10:36
1190 ppm Fri April 14, 2017 12:44
1200 ppm Mon April 10, 2017 13:45

I'm seeing some BTN on my LPS corals, not sure if that is from the alk swing? Or all the parameters.

My question is how do I stabilzie all these parameters? Seems like one goes up and the other goes down, then I adjust and same thing. Water changes dont seem to affect the parameters much.

Should I just measure alk every day and adjust if I see a trend in the wrong way? Same for calcium, but measuring 2xweek or weekly?

Thank you for your help