Safe paint for sump

[mfinn]

I understand the proactive side of trying to limit algae from growing everywhere in the sump, but both my currently running sumps have a refugium area. But algae doesn't really grow anywhere, except on the inside walls of the refugium. I don't have any to speak of. I do get hair algae growing over the baffle coming from the skimmer side. But it just wipes off. I usually only clean it when I harvest the cheato and stir up the refugium.
My biggest issue is algae growing on the inside of the skimmer bodies.
At one time I did have a black plastic film over the outside of the skimmer body, and that helped.

 

[UncommonSense]

My biggest issue is algae growing on the inside of the skimmer bodies.
At one time I did have a black plastic film over the outside of the skimmer body, and that helped.

I’ve had luck wrapping a skimmer body in a piece of pond liner material, Reinforced Polyethylene (RPE) liner material in this case!

It’s also available with a specific UV protective coating (which should last indefinitely in a sump, when designed to live outdoors in direct sunlight for a decade plus!)

 

[Euphylliaphyle]

I used a peel and stick black vinyl to cover part of my overflow box. Seems to be holding up fine after 4-5 years.

This is my black background on my display. Its static cling, room darkening (blackout) window film. Looks good as long as you get all the bubbles out at installation time.