Cal, mag and alk

[Robbie_b]

So i started my 90g with fish only and now im wanting to start getting it ready to add corals. So i bought salifert testers for cal, mag, alk, phos and nitrate. Tested it today and here are my results

Cal - 310
Mag - 1200
Alk 15.7
Phos - 0
Nitrate - 0

I know i need to bring up cal and mag, but will my alk go down once i start adding corals? I want to dose the brs 2 part.

 

[JimWelsh]

What is your salinity, and how are you checking it? With both calcium and magnesium low, that points to likely low salinity.

 

[Robbie_b]

Its right around 1.021 and all my test are the salifert test kits taking it right out of DT.

 

[lapin]

Water changes with a good salt mix should bring your numbers in line if you keep your salinity at 1.025-1.026
I would not worry about dosing just yet.
You want 400 to 500 calcium with 1400 to 1500 mag.
What salt are you using?
The high Alk is an issue. It will not go down until your corals start to show some growth. With no nitrate or phosphate the high alk will burn/bleach the coral.

 

[JimWelsh]

Its right around 1.021

Again, how are you measuring your salinity? Assuming 1.021 is accurate, then simply raising your SG from 1.021 to 1.026 would bring your Ca up to around 380, and Mg up to around 1480.

salinity at 1.205-1.026

I think you mean 1.025 - 1.026.

400 to 500 mag

I think you mean 1400 to 1500.

 

[Robbie_b]

Im using a hydrometer and im using IO

 

[lapin]

Ya I was a big hurry when I typed that. I fixed it

 

[JimWelsh]

Im using a hydrometer and im using IO

Swing arm or floating type? If swing arm, then know that they are notoriously unreliable. You might consider getting a refractometer.

 

[lapin]

IO should mix to 9 to 11 alk at 1.025

 

[Robbie_b]

It is a swing arm and looking into getting something better

 

[rmurken]

You might want to do your Alk test over again. That’s unusually high for any salt mix, much less IO, and definitely doesn’t sound right for IO (or anything else) at 1.021. You might also want to re-test everything else also just to be sure.

 

[JimWelsh]

You might want to do your Alk test over again. That’s unusually high for any salt mix, much less IO, and definitely doesn’t sound right for IO (or anything else) at 1.021. You might also want to re-test everything else also just to be sure.

Agreed. Also, make sure you aren't overshooting the alkalinity endpoint color. Please see this thread: https://www.reef2reef.com/threads/alkalinity-titration-endpoint-ph-salifert-endpoint-color.543556/

 

[rmurken]

Agreed. Also, make sure you aren't overshooting the alkalinity endpoint color.

Brief aside—not hijacking the thread...I use the Red Sea test (blue with green endpoint, then yellow if you overshoot). Drives me nuts. I have my 8yo do it with me sometimes and we both judge the color.

 

[Vinman]

I like a refractometer for salinity test. Also you can check it for accuracy using RO water

 

[JimWelsh]

Also you can check it for accuracy using RO water

Only if you're trying to measure RO water. If your goal is to measure a reef tank's water, then you need to use a proper calibration solution. Please see: http://www.reefedition.com/refractometers-salinity-measurement/

 

[Vinman]

Only if you're trying to measure RO water. If your goal is to measure a reef tank's water, then you need to use a proper calibration solution. Please see: http://www.reefedition.com/refractometers-salinity-measurement/

Thanks never knew there was such a thing always just used RO water and zeroed out