Consuming mag; Alk up & down

[MarcS]

Hello everyone. New guy here and my first post.

I have a 120 mixed reef that I bought used in October last year. It's an old tank that seemed to be neglected for a long time.

I upgraded the old filtration system with a Triggertime refugium sump with filter socks (chaeto is growing well and there's about 5 gallons of live rock in there), Phosban 150 reactor, ATO (Tunze?), added lots of live rock to the display tank and replaced the MH with LED lights. I got a 4 cylinder filter to make my own rodi water and I do a 15% water change every 10-12 days.

I started paying closer attention to my parameters and I'm worried about them being so inconsistent. I'm also worried about how much magnesium I'm consuming.

Here are some recent results from using Salifert test kits. Much of this seems contradictory and it makes me wonder if I'm being careless in my technique with the test kits so now I'm being much more careful and following the directions as closely as possible. I periodically check for phosphates but I never get any noticeable amount since running the refugium. Also my salinity is stable at 1.025 in my refractometer.

........................Alk/dKH...............Calc................Mag
3/10......................8.6..................440..............1200

3/12......................8.5..................425..............1270

3/16......................8.5..................415..............1220

3/19 Water change

3/20.....................9.3!!.................400...............1220
...........Dosed-.........0.....................60ML.............90ML

3/2.......................8.0...................420...............1220

3/22.....................8.2...................420...............1170
............Dosed-......30ML................90ML.............150ML

3/23 9AM..............8.0...................420...............1215
..........Dosed-......90ML.................90ML.............150ML
3/23 Noon.............8.7...................435...............1190

3/24.....................8.3.............(didn't test)..........1170

3/25.....................8.2...................430................1150
..........Dosed-.......30ML................30ML..............150ML

3/26......................8.3..................440................1180
............Dosed.........30ML.................0..................150ML

3/27......................8.6...................445................1200


Do you see any red flags in here? Any idea what the heck is going on? My fish are healthy and almost all of my 50-60 pieces of mixed coral seem happy.

Marc

 

[bertoni]

There's enough noise in calcium tests that such frequent testing won't help much. I would test alkalinity daily and dose accordingly for a while. I'm guessing that you are using a 2-part? Measuring calcium once a week should be fine. As you've seen, water changes can affect the parameters a lot, and that will require some measurement, as well.

The magnesium numbers seem reasonably consistent with the last few doses, but the doses are quite small, and the kits are only so precise. This calculator will show you about how much to dose:

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

I might check magnesium once a week for a while.

 

[MarcS]

Thank you Jonathan. I get my minerals mixed in a gallon jug at Keith's Coral Reefs in San Jose. Keith is a great guy and I go in there quite often since it's 5 minutes from my shop were I keep my tank. I don't know what products he uses to make them.

If you're ever in San Jose I'd love to have you come see my tank. I promie to try to keep my questions down to less than 500

 

[NEWB2004]

Hey Marc,
It's important to set up a regular dosing cycle, so the tank becomes stable, and consistent. My tank is on a doser that doses daily in small increments. I suggest using a good reef calculator like the one Jon mentions above or use BRS(Bulk Reef Supply).

You will need to decide what values you want to shoot for. I like Mag=1350 Alk=8.5-9 and Clacium =430-450.
You will need to use an appropriate method to initially raise the parameters to get to your desired levels. Once at the desired levels, allow a couple of days with no dosing and then measure again. This is your baseline usage rate of the tank. You will then look at a dosing calculator and make a determination on how much to dose daily. Then start that dosing regimen and do not deviate until you measure again after a week. You will then see if it is maintaining or you need to make adjustments.

You should only need to adjust the Mag after each water change. In my systems, it has never been depleted between WC's, which I do monthly at about 40% of total volume or every two weeks at approx. 20-30 % of total volume.

I hope this helps. The guys on RC are great and really smart andwant to help so please make sure you ask any and all your questions.....
Ted

 

[navek65]

Hi im new to this and setting up a reef tank well ben running now 6 months , but im not sure if i have a problem , its around 300 l (65gal) with 100l sump , iv only live rock and two fish , plus pulse coral , my po4 is fine , as is my no2 and ph and density 1.024 but i wanted to try and build up coralline algae , before i added and more corals , i ask in my local fish shop and he gave me kh coralline gro , but im not happy with my ca and mg readings and can anyone give me any answers to get these right , as my ca was 800, and mg 900 many regards and as much help needed

 

[MarcS]

Thank you for that. I've considered getting a dosing pump before but I keep getting coral instead. I'll start shopping for one. Let me know if you have any recommendations.

Marc

 

[moatdaddy]

Hi im new to this and setting up a reef tank well ben running now 6 months , but im not sure if i have a problem , its around 300 l (65gal) with 100l sump , iv only live rock and two fish , plus pulse coral , my po4 is fine , as is my no2 and ph and density 1.024 but i wanted to try and build up coralline algae , before i added and more corals , i ask in my local fish shop and he gave me kh coralline gro , but im not happy with my ca and mg readings and can anyone give me any answers to get these right , as my ca was 800, and mg 900 many regards and as much help needed

http://www.reefcentral.com/forums/showthread.php?t=1179702

read this, then also watch BRS videos on youtube. I think week 29 is alkalinity calcium and mag.

 

[NEWB2004]

Marc,
I bought this one. I have one of their dc runner main pumps that I really like also.

http://www.amazon.com/Aqua-Medic-Re...&redirect=true&ref_=oh_aui_detailpage_o01_s00

There's a number of ways to go if you have a controller, you can even get get individual pumps from BRS.

The key is stability.... and it lets you go away for the weekend and the tank is on autopilot..... or that's the way its supposed to work lol. Enjoy!
Ted

 

[NEWB2004]

Marc,
I forgot to mention that you can dose the mag up to your desired level and usually not worry about it until your next water change. Again jons calculator or the one on the brs site. You can test again to confirm the dosing after the water has turned over a couple times in the dt.

 

[sixpackgarage]

BRS says in their videos I believe that you should dose mag about half the rate of alk and ca. I believe this to be true. For me to maintain constant roughly 1320 mag, I need to dose about 30ml per day, which is actually roughly half what I dose for alk and CA. I now use my doser plus kalkwasser, so I no longer have exact data, but I believe it to be true.

I have also own 3 different brands of test kits and all give me different results. I usually use Red Sea, but if something looks odd, I'll do a back up test with another brand of kit just as a sanity check to make sure I'm not making testing errors.

 

[downbeach]

What salt mix are you using? Have you calibrated your refractometer? With what, i.e. water or a 35ppt calibration solution.

There's a proceedure I think it prudent to follow to help to minimize the affects of WC's on dosing.
First, as a precaution, if you're not using the entire package, would be to thoroughly mix the salt mix to make sure there was no elemental stratification that may have occurred during shipping, and you're getting the proper proportions of all the elements, i.e. Ca, Mg, Alk, etc., with each measure of salt mix when you make up your WC water.
Secondly, following proper mixing procedures, i.e using RO/DI water, adding the salt mix to the water, etc., I would make sure to accurately get the SG you want, I preferred 1.026(35ppt), using a properly calibrated measuring device, i.e. refractometer calibrated with a 35ppt solution(not plain water), to ensure the same amount of these elements with each WC. Using a swing arm type of hydrometer, or other non/mis calibrated device can cause differences in your SG when you make up your WC water, and further skew a dosing schedule. Using a decent set of test kits, i.e. Salifert, Red Sea Pro, etc., measure your Mg first, making sure its between 1200-1400ppm, then your Alk and Ca.
Next, I would set and keep a schecule of WC's in terms of both frequency, i.e. weekly, bi monthly, monthly, etc. and volume, i.e. 10%, 15%, 10 gal.,15 gal., etc. to help minimize any skewing that may normally occur, since this is where you're adding/replenishing those elements in an ongoing basis.
Depending on a particular load in any system, it's likely that you may need to adjust your dosing based on a particular WC schedule, i.e. the disproportionate use of Alk vs Ca supplement, since the WC is better at keeping up with the Ca needs. You may notice that, with regular WC's, you may never have to dose any Mg, since there is very little of it used(about 1/10th of your Ca use), and its replenished with regular WC's.

 

[bertoni]

Every tank will be different in its magnesium consumption because different organisms use different ratios of calcium and magnesium:

http://www.advancedaquarist.com/2003/10/chemistry

My tanks never needed magnesium dosing to keep up with consumption because the drop was very slow. I had lots of coralline algae growth, but no stony corals.