Sorry, we may have had some confusion here. One of your earlier posts stated that your specific gravity was all the way down at 1.09....which I interpreted at 1.009 but I now think it was obviously just a typo and should have been what you stated above.
1.019 is low for a reef, but most fish could live in this without issue.
I will eventually give it another shot and let it go for about two hours or more.
Don't worry much about "x" amount of time. Measure the specific gravity of your tank water (QT
tank preferred!) and compare it to the measurement of the LFS
specific gravity. When they are close, the fish should do just fine.
I normally place the bag in the QT
tank and drip water right into it (removing some and discarding as it fills). This way the temperature matches that of the environment. If this is not possible, a heater would help as long as it is set and monitored to be holding the correct/desired temperature.
One of the other important notes in acclimation is to NOT add LFS
water to your tank, this is a common way of introducing parasites and other nasties.