Can I use this as a standalone co2 diffuser without the canister?

No not really as it depends on the water flow to move the CO2 bubbles from the lily pipe into the tanks water column.

Where can I find a filter guard for this inflow/skimmer?

Amazon. Buy the smallest one you can find and it will work. Nano filter suction foam guard.

The surface skimmer is really noisy. I tried turning the bottom but it didn't really help. Any suggestions?

That means it is sucking lots of air, what I did, I let the filter acumulate more detritus than usual, that slows down the flow. Also, pull down the adjusting knob towards the end of the bottom intake, almost where the "O" ring, that opens a bit more space for water to go through the bottom and not trough the skimmi g top. With time, the skimmer portion will be cover by bacteria, this also allows for smoother water flow, reducing turbulence there fore reducing noise. I hope this tips are of assistance, please pardon my English. Good luck!

Is the adjustable neck on the outflow removeable for cleaning?

The adjustable neck is removeable for cleaning and the lower end of the return pipe is also adjustable.....it regulates the amount of flow into the filter from the pipe. I found this set-up to be one of the best I've ever used. My water is crystal clear and there is no film on the water, ever. I use CO2 and my tank is heavily planted. I'm glad I purchased this item.

Package Dimensions	20.8 x 13.9 x 11.9 cm; 280 g
Colour	Brown or Green
Size	13MM SKIMMER SET
Quantity	1
Special features	Durable
Specific Uses	Aquarium
Batteries required	No
Batteries Included	No
Item Weight	280 g

Nano Aquarium Lily Pipe SET with Surface Skimmer for 12/16mm Hoses - Mini Glass Inflow & Outflow for Small Fish Tanks

Details

Description

Specifications

Common Questions