Oil slick on tank while water testing

[ScottD]

Success, now let’s see if it comes back. I’ve got to admit, I was really skeptical about that working but it did. I should have taken a before picture, but here’s the after pictures.

 

[ScottD]

I do plan on draining the tank and filling with fresh water. I wanted to first try and get rid of the slick before draining it though so it wouldn’t cling to the rocks or tank sides as it drained and still be there when I refilled it. I’ll probably give it over night to see if a new slick appears in the morning and drain it then. Thanks everyone for their help and suggestions, I greatly appreciate it.

I do agree with @thedon986 that the initial was powder from the Marco rock. After the first time I siphoned off the surface it changed in appearance, I think because I got all the powder off and just an oil slick was left.

 

[Dom]

Now, we wait.

 

[Sumbub]

Don’t forget to wipe the edges of the water and overflow box where the water touch if/when you drain.

 

[ScottD]

Don’t forget to wipe the edges of the water and overflow box where the water touch if/when you drain.

Thanks, yes I had plan on that. There’s a scum line at the high water mark. Planned on using a magic eraser pad to wipe everything down.

 

[stewy14]

is it biofilm maybe? from lack of flow and stuff?

 

[ScottD]

is it biofilm maybe? from lack of flow and stuff?

It’s possible, but not sure I’d expect to see that in a tank that has just been filled and only has rodi water and dry rock in it.

 

[ScottD]

So I ran my wave makers over night and then let the tank sit still for 4-5 hours and saw a just a hint of an oil slick on top of the water, I’m hoping just some residual. I emptied the tank and working on filling it back up again and will keep an eye out for more. My plan moving forward is to use cling wrap again if it shows up again and regardless I’m going to run some carbon in a filter sock to pull out anything remaining.

 

[Sumbub]

So I ran my wave makers over night and then let the tank sit still for 4-5 hours and saw a just a hint of an oil slick on top of the water, I’m hoping just some residual. I emptied the tank and working on filling it back up again and will keep an eye out for more. My plan moving forward is to use cling wrap again if it shows up again and regardless I’m going to run some carbon in a filter sock to pull out anything remaining.

If it’s residual you could probably use carbon and save the water you have currently. Oil and water don’t mix after all. Now I’m curious if Marco rock uses a mold to make their rock and use a release agent.

 

[ScottD]

If it’s residual you could probably use carbon and save the water you have currently. Oil and water don’t mix after all. Now I’m curious if Marco rock uses a mold to make their rock and use a release agent.

If you look at the internal holes and tunnels running throughout it you can see that is a natural rock, not man made.

I had poured some tap water in at one point to help keep the water above the top of rocks so needed to drain it out.

 

[Sumbub]

Ahh okay I got it.