Low Alkalinity ?

Hi I have my tank RSM 130 running now for 6 weeks the tank cycled and I have 2 clowns and a cleanup crew and 30 lbs of live rock. The problem? is the Alkalinity is at the bottom of the scale or even to low? any ideas ?
Temp 78.8
Salinity 1.026
Ph 8.2
Alkalinity 2.0
Calcium 420
Ammonia 0
Nitrite 0
Nitrate 0
I have added Coral Buff once a week..... any help greatly appreciated

 

Ok maybe that explains why it wont give a reading from our test kit
So why would it be out of whack and what do I do?

 

I have the Test Kit that came with the RSM but when testing the magnesium it wouldnt turn to any colour on the strip (so we thought it might be old, test kit?) as for salt I started with the RS pro Salt, and now (last 10% water change) Reef Cystals, wife is trying the test again (mag)right now..........

 

So OK tried the test again (Magnesium) and when adding the reagent drops the colour change that is suppose to happen doesn't??? we have Magnesium Supplement but it says don't add unless Aquarium is established a minimum of 3 months and we are at 6 weeks?

So I am thinking we need a different Mag test?

 

My questions are 1.) What kind of test are you using? and 2.) is it expired?

 

Test Kit is called Marine Lab by Red Sea and expiry is Aug 2010

 

Hmmmm. So if you add the entire 1ml, I would presume that means you have a value of over 1500. That's the way mine works. Did you draw another ml of reagent and continue to add? With mine, each 0.2ml of reagent added indicates a jump of 30. So it I add 1.04mls (which is what happened last time), I come up with a value of 1560.

 

Yes we added the 1st ml and it was suppose to turn blue but only went purple? added another full ml and still stayed purple?