need advise on very low alkalinity kh .

[Reef257]

Hi all
Hope everyone is doing good

I tested my tank water seem like the kh is very low its around 7.0

I planned of increase it 8.4 .which would be the best approach . With stressing the coral .what water change is due tomrrow

I have 125 gallon Mixed reef tank

1 do I need to dose alkalinity to increase Than do a water change

2 or should I do the water change .so it's back to normal .how much percentages should I Change.

I use red sea alkalinity
And red sea salt (not the coral pro)

Once it back to normal thought of using red sea skeletal elements to balance all for future.

Thank you .wish me luck
Current Test result
Ph 8.0
Alkalinity 7.0
Calcium 450
Magnesium 1600
Salinity 1.025

 

[Chuk]

I would say do the water change then retest. Assuming you do a 10-15% change it will take your alk up to 7.1- 7-15. If you dose then water change you are basically throwing again chemicals. After you retest add enough to go 1/3 to 1/2 of the where you want to go. Retest the next day then repeat until you get to where you want to be.