Depends on how much water is changed. A 10% water change will not increase calcium that much, imo.

Here are some articles to read. Heavy reading at times, but will help you understand reef chemistry better:

Solving Calcium and Alkalinity Problems:

http://www.advancedaquarist.com/issues/nov2002/chem.htm

Magnesium in Reef Aquaria:

http://www.advancedaquarist.com/issues/oct2003/chem.htm

Reef Chemistry Calculator:

http://home.comcast.net/~jdieck1/chem_calc3.html

Ya, sorry. I mean a good water change, like 50% or more.

thank you , will do you all have been a big help

If your lfs is giving you wrong information I'd talk to the manager and let them know all the trouble you've been through. That being said, it does sound like you had a precipitation problem. Keep us informed.

Doug

just me
 

i took your advise read some of those articles, like that calculator
did a 50% water change will test water tomorrow thanks