Water temp variance

[Reef Pilot]

I have just set up a 30g refugium tank to share the same sump as my main 100g display tank. I have it plumbed so that I can separate it from the sump and also use it as a QT tank for new fish. But at some point would like to connect it again to acclimate the new fish to the DT water before moving them to the main DT.

However, I currently have it set it up so that my chiller outputs to the refugium, before the water flows back into the sump and mixes with the DT water. That causes a 2 or 3 degree F gradual temp drop and then back up in my QT tank as the chiller does its job. This cycle happens about once an hour.

What I am wondering if this temp variance is enough to adversely affect the new fish. I could get around this, by adding an additional pump in my sump and not send chiller water directly to the QT tank. But not sure if this is really necessary.

Walter