CUC after their job is done?

[Ztrain]

So I have completed the cycle and had the 2 clowns, Trochus snail, and one sulking scarlet reef hermit in my tank for 5ish days now. I have a 20g with 20lbs of dry rock and seeded the system with 2.5 of live rock. All the algae and food and stuff was on the live rock. So since it is mostly empty of this I only got the two of the CUC. I didn't want them to eat everything and die off. I'm starting to see some brown patches forming on the acrylic and green and brown tinges on the dry rock. I'm doing bare bottom and don't want to have to save snails each day so that limits the snail choices. What would be a good clean up crew for this size of tank?

Then after they remove all or nearly all the algae what do they live off of? I don't want them to die off but most of my rock in my tank is bare atm. Not sure what to do CUC wise.

 

[fishhuman]

Fishfood that falls to the bottom and fish poo

 

[fishhuman]

Algae will grow back soon

 

[Ztrain]

Fishfood that falls to the bottom and fish poo

With only two baby clowns about half an inch each that's not a whole lot. They don't get a whole lot of food but that's for the Clownfish forum to tweak out. I don't have anything else in the tank I directly feed. On one hand that one Troch has put a pretty major dent in the algae but if it starts sprouting up all over I think I'll need more than just him to keep the yard clean.