Pond Boss Forums GENERAL QUESTIONS Water chemistry Not sure this is a water question but...

In one section of my pond I am developing an orangy brown algae-like slime coating the rocks/bottom. It is tricky to describe however I believe it has something to do with water flowing into the pond through an area of rotting vegetation. The water coming in has this strange orange tinge to it along with some shiny flakes of orange as well. (Not gold I am afraid and there is also a bit of an oil-like slick associated with it). I wish I could describe it better.... anyways the substance forms rapidly and has no real substance if you try to pick it up... any ideas out there?

As a kid I used to like to make dams in small streams or to dam up the drainage ditch to the local abandoned gravel quarry to make the water deeper. I would often see this orange slimy stuff on the back of the dams where the water would seep through. I often used sod and/or pine sticks and branches. I think this orange stuff was some form of fungus living of of the rotting materials. Yes and I would get what looked like oil slicks too.

Hey Brian,

Sounds like you were seeing exactly what I am into... I will assume that it is relatively harmless.

Same here to , forms on minnow buckets,trees i've added, rocks, dock post's,etc. but does'nt seem to do any harm. Harvey

Forgot to mention land around pond is heavely wooded have lots of leaves fall around and in the pond

Its algae, easy to id because the sheen it leaves will crack apart if you touch it. If you touch oil on the water it will coat your finger.

Shan

Guys - All your symptoms including the oily/stagnate film indicate that you are dealing with iron bacteria. Do a search on Google or other engine for information about it.

Also the reddish coatings could be "yellow boy" or iron hydroxide. Streams in strip mine areas often have a lot of this. Iron hydroxide is soluable at low pH and forms a precipitate (ferric hydroxide) when the pH increases. Yellow boy varies from brown yellow to red orange and after sedimentation can form encrusted deposits up to 1/2" thick.

Some algae can appear orangeish-brown but I doubt that is your problem. Often iron bacteria will coat periphyton algae that is attached to underwater substrates.

BC is right on. Also Iron percipitates and causes the oily look on the surface. this is more common in stagnant type ares with little flow, kinda like when you dam up a creek as mentioned.

BC and GG...But is it harmful?

BC probably knows better than I, but I dont think it is harmful. It just looks bad. I could cause a problem when trying to irrigate with a drip system due to the iron particles.

Harmful to who? Algae, invertebrates, tadpoles, fish, humans? Harmful in what respect? Eat it, live in it? Harmful in what form soluable, percipitate, bacteria? Drink soluable iron?. Stain porcelin? Clog pipes?.