Horror in my loop

[Lome]

Im realy not sure how algae can grow without nutrients in the loop, ...
not to mention the co2 and oxygen that would be required for algae to grow.

[spitter3]

Im realy not sure how algae can grow without nutrients in the loop, you guys sure you arent pissing and ting in the res before starting it up?
not to mention the co2 and oxygen that would be required for algae to grow.

Algae only needs water and co2 and a little light to grow. Autotroph.

[shazza]

Hard to tell without analysis ... but it's also possible those gray bits are pieces of tissue that have worked their way into the block. Did you ever use any thing to dry the inside portions of your fittings that could leave this type of residue?

[Conumdrum]

Betcha thats leftover chunks in your rad. Like a scab, they fall off sooner or later. I don't see growth, just blobs.