UV sterilizer with yellow staining on output hose.

[Velcro]

has anyone ever heard of this? The input hose is perfectly clear and the output hose has a yellow tint. This is a slow flow (150gph) through a 55 watt UV that I added months ago to get rid of ostreopsis dinos (it did so in about 48 hours).

I've kept it running since, but I've noticed the output hose was brown when it was in the path of light. Now that I moved it to an unlit area with new hose it's yellow on the output. I'm considering feeding a carbon reactor from the output of the UV.

 

[Alfrareef]

Can't help since my return hose (which was transparent) has a yellow tint all over.

 

[Flameback Pair]

UV light energizes Oxygen molecules somewhat and some become Ozone. Ozone is produced by UV units in small amounts and Ozone is a powerful oxidizer. You can get Ozone/UV resistant hose.