Light Brown Film in Water Storage Container

[FallChinook]

We use Instant Ocean and RO/DI water that we mix up in a 45 gallon trash bin (new and rinsed). We have a Koralia 3 and 4 in there constantly mixing the water and a heater set at 78F. I am noticing a thin light brown film that feels chalky on the surface of the bin. There is a heavier coating on the pumps, heater, and power supply lines that are submerged. Any ideas????

 

[newreefguy]

Can you scratch it off with finger nail,wipe it off?

 

[FallChinook]

Yes, you can wipe it off with your finger.

 

[newreefguy]

I was going to suggest precip. But I've never seen brown precip. So I would say its just some form of algae... but im just a new guy so the pros would have to give you a better idea.

 

[newreefguy]

Now that I look at it my mix tank has the same stuff... but I use well water, test weekly for "bad stuff"

 

[BLAKEJOHN]

It is calcium precipitating out of the water. I have it too and I use RC. At first I thought it was a bad crud and then realized, If I only let the mixed water sit there for 2 days I wont get it. After 2 days the calcium starts to precipitate.

 

[FallChinook]

Yeah, that's what our LFS told us yesterday--calcium. That would make sense because our calcium levels are dropping and we always do weekly water changes.

 

[Boomer]

The soft "brown stuff" is usally a binding and or anticaking agent of some kind