white mucus/slime on top of water?

[stingeragent]

That slime is from not enough surface aggitation. Same principle if you take a glass of water and let it sit for a week. It will have slime on the top. Point a powerhead towards the water surface. I get the same slime in my return section where there isn't much flow. Just drop a small powerhead in just below the surface. Will take care of it in no time.

 

[splix]

Neat on the printed overflows. What'd you make them out of? PET+?

ABS. PLA/PET etc will decay in salt water. ABS will hold.

 

[Bogue Chitto]

Those printers are amazing...