PH and Alkalinity

[zzman]

This may be a dumb question but my chemistry is "0" !

120 gal reef tank, 5 small fish, mushroom coral, acropora coral, colt coral and some small yellow hairlike coral. All have been in the tank at least 6 months. The Colt coral split 3 times and now is 1/3 the size it was. I noticed the small hair like coral is only opening about 1 hour a day. The calcium level is low so I dripped lime water. The water para. are:
PH - 8.1 (checked with digital meter)
Alkalinity - over 250 (checked with strips)
Calcium - 380 (checked with strips)
Am NH3 - 0 (checked with strips)
Nitrate #3- 20/40 (checked with strips)
Nitrate #2- 0 (checked with strips)
S.Gravity - 1.023 (checked with digital meter)
Temp - 77.2

My question is how can the alkalinity be so high if the PH is were it should be ? Should I lower the PH to bring the alkalinity down?

Thanks from a 0 in chemistry !

[marineaddict]

I would doble check your readings with a more accurate test. IMO, test strip readings are not worth much.

[zzman]

The ph meter was calibrated at 7.0 with a digital electronic meter,
I don't know of any electronic meter for alkalinity
I do have the test tube type test for alkalinity and will retest

Thanks