Ok, I was feeling nerdy and while calculating the needed salinity level of my water change to raise the tank from 1.023 to 1.025 I worked out a formula, attached as a pic, to determine that in actuality my 150g DT + 30g Sump only had 98g of water in it. In other words, my rock, sand, skimmer, etc...was displacing 82g of water. So that had me thinking, when I dose supplements do I use the 180g total, like I have been, or do I reduce the amount to whats appropriate for 98g?

Tank Volume Formula.jpg