ya i understand that about needing 2 tests, but here is the deal with my LFS. they dont test their water at all. I asked and they only use the DI filter and add calc and stontium to tanks every other day. I looked for a calcium test and they didnt have any there. told me they dont stock them. When asked why he dont test for it he told me that he dont fix what aint broke. i took their water and tested it when i brought my coral back. It tested at like 440-460. i have been using test to test water and such and get same readings when testing tap water, DI water, Mixed water and etc. each test varies for type of water testing but always is consistant. I do think my test is accurate tho. I did add an alk additive to get the calc to precipitate, but plan on stopping if corals make it through the night. after water change of 2.5 gal and adding alk additive my water calc went from 575 to about 490-500PPM so something is working. even if oxygen is not needed it adds a flare right now in the tank. thanks for all the help guys ill keep you posted in AM when i check on them.