Something ate my refugium

[mikeweber3]

BACKGROUND
I have a 240 display mixed reef and fish. It recirculates with a 180 refugium. The refugium has been up and running great for years with no trouble. I use a calcium reactor. I use no mechanical filtration. About 8 square feet is dedicated to plants. It has Caulerpa, Cheaeto , and some very long leaf algae. There are quite a few small shrimp and pods in the refugium, but no fish or large invertebrates that I know of. There are dividers in it that does have live rock where some unknown enemy might live. The refugium is in a separate room and I don't check it often enough. I have a Neptune Apex controller that alerts me if anything gets out of whack. I have always had to prune the plants about every two months.

CURRENTLY
Today I went in to check and WOW! I hardly have any plants left. What is left is all laying on the bottom. It's like someone ate all of the stems, all of the berries, and most of the leaves. It does seem like I see a lot more shrimp than normal, but maybe that's because there's no plants for them to hide in. My display tank looks fantastic and all of my numbers are great.

QUESTIONS
Where did my plants go?
How do I fix it?

 

[Michael Hoaster]

It's possible you have Caulerpa Slugs. I had a population explosion in my previous tank. They can wipe out your plants. Then they will die when their food is gone.

Also another possibility is your nutrient levels may be too low to support plant growth. You said your numbers are great. For a reef? Reef level nutrients aren't adequate, especially for fast-growing green macros. Slower growing reds or sea grasses may work better.