P.S.- what is that little meter on the side? Amonia? trustworthy? Just curious.
That's a Seachem Ammo Alert Badge. IMO they're an absolute must and savior in a QT tank. They last for a year, and constantly monitor ammonia levels, the #1 killer in QT tanks. I recommend everyone have one in their QT to monitor ammonia quickly at a glance. They're cheap and literally life-savers! You can get them from Premium Aquatics, the Tropicorium (usually) and likely many other vendors.
What should someone do if their ammonia gets too high? Also, how big is that QT you have?
As mentioned do a water change. I always do 100% water change prior to adding fish into my QT, and keep fresh mixed saltwater on hand. In the event of high ammonia change at least 75% of the water to immediately relieve stress (of course, try to prevent ammonia spike in the first place).
The height I run the water at it holds 18.5 gallons. It's about 22" x 20" x 14"H.
What should someone do if their ammonia gets too high?
Since posting this a couple years ago I've also used Ammo-Lock from Aquarium Pharmaceuticals with success. However, if you're using any copper based medication do not use it, and stick with water changes.
Great post ! QT is a vital part of reefing not just for fish but for coral also. It is much easier to treat a fresh coral that is infected in a small qt as well as fish. It is also important to have a qt so if you do find an issue or pest it can be treated quickly. I usually do a water change in my DT to fill my qt. I use a 20 gal is all. You do not need to have a huge qt unless you buy huge fish and coral lol I usually QT fish for a few weeks and coral for 4 to 6 weeks unless I get it from sources that I truly trust and am familiar with their QT practices