Help with Mg and PH

CSJIII · Oct 18, 2011

I need some help concerning some of my perimeters of my tank. I had let me tank for for a few months and about a month and a half ago I went back to keeping up with my tank husbandry. I have quite a few zoas, some SPS and some chalices. After getting my hair algae problem mostly under control, I have been dosing 2 part, PH buffer and Mg. My salinity is 1.026. my DKH is 6-7 at best and my ph is around 7.8-8.2. I was dosing Mg under the assumption that all of my levels were low from lack of care taking and after dosing 5ml every night on my 28 gallon system I decided to test it. IS IT POSSIBLE THAT MG Mg IS AT 0? I have a brand new Salifert Mg test kit and it tests at zero even after my dosing. Is that at all possible? I am trying to get back on track. Help is appreciated.

Mojoreef · Oct 18, 2011

Is that at all possible?

nope

stedfast82 · Oct 18, 2011

get a new test kit your system will do well at mag 1500 PH and alk will all come into play later .ph i dont even have a test for that .ph will never come into play till your system get's all good don't play the # game just take it easy if your not killing anything then leave it alone it will all come out good

VegasRick · Oct 18, 2011

From the estimates I have seen Mg consumption is only around 2-3 per day with heavy coraline growth, you have to neglect it for a long time to for it to get low. Water changes usually keep it in proper range. Test again and if it still comes out 0 get another test kit. Most salts have 1300+ Mg and NSW is around that number. I would focus on getting your alk stable somewhere between 7-10

CSJIII · Oct 18, 2011

The test kit is brand new but I did buy a backup. I will test tonight. It's strange but if you're firmilar with how the test works, you mix 2 ml of tank water and mix in the proper chemicals then to get the reading you fill a syringe to 1ml of the final chemical, you add it drop by drop till it goes from pink to blue. When it changes, you take a reading of how much chemical is left over. It always turns blue on the last drop which means a reading on zero magnesium.

VegasRick · Oct 18, 2011

It's probably impossible to have 0. Not familiar with the test, are you sure its not off the scale in the other direction? I know a few people who were dosing heavy with out testing and ended up with 1800+. If you are doing water changes there is no way its 0. Theoretically if you had 0 and did a 25 percent change and the salt content Mg was 1300 then you would have 325.

Lytehouse · Oct 18, 2011

CSJIII said:
The test kit is brand new but I did buy a backup. I will test tonight. It's strange but if you're firmilar with how the test works, you mix 2 ml of tank water and mix in the proper chemicals then to get the reading you fill a syringe to 1ml of the final chemical, you add it drop by drop till it goes from pink to blue. When it changes, you take a reading of how much chemical is left over. It always turns blue on the last drop which means a reading on zero magnesium.

Changing on the first drop should be a reading of zero. On the last drop should be pretty high.
On my Salifert kit, turning on the last drop is about 1500.

CSJIII · Oct 18, 2011

Lytehouse said:
Changing on the first drop should be a reading of zero. On the last drop should be pretty high.
On my Salifert kit, turning on the last drop is about 1500.

It changes to pink on the first drop. When it turns blue is when you take the reading which corresponds with the amount (ml) left in the syringe. I will pick up a new test kit tomorrow. My kh just tested at 10 with a cal of 380. Ph fluctuates due to lighting from 7.8 to 8.16 at lights off. You can see my ph as of 9:58 this evening

VegasRick · Oct 18, 2011

A pH fluctuation like that is normal, although it is a bit on the low side. Low pH is usually from high room co2 or poor gas exchange. Open the doors and let some fresh air in. Increase water movement at the surface to promote better gas exchange. If its closed canopy you might try opening it up or the sump area to let more fresh air in. Using Kw will also help raise pH 2 ways. First it has a high pH to start with and will raise pH just by adding it to the system. Second it combines with the co2 in the tank to form carbonate that corals need.