Brown Salt Water mix

[STEVE]

I went to do a water change last night, I've had it mixed, and kept at 78 degrees for about 3 weeks with a pump keeping it moving....well anyway, I look at the water and there is light brown residue everywhere, WHAT THE....?

[Max Ivers]

what salt mix do you use? I've heard this occurs with salts that are made using dehydrated ocean water (D+D H2Ocean, Red Sea Coral Pro). I personally use D+D and I do notice a brown residue on my BRUTE container. To prevent any issue I run my new water through a 100 micron filter sock when I pump it into my tank for a WC.

[GraffitiSpotCorals]

I notice a brown film buildup on the inside of the trashcan I use but I wipe it down every now and then and never worry about it, I am using instant ocean. Is the water brown or just the inside of the trashcan?

[STEVE]

Kinda freak'd me out....It's all over the heater, the pump and the trash can.

[Jan]

Sounds like diatom algae, which happens in storage tanks. It's no biggy. Check the TDS on your RO/DI water, not the mix.

[RubberFrog]

I stopped using redsea because of the brown film. I use reef crystals now and that doesn't happen any more.

[beatle]

Odd, RC had the most brown film for me. I'm back to IO which seems "cleaner."

[Steve175]

Reef Crystal often does this both IME and per Reef Central. I have always still just used it. Not an issue. Agree with confirming the quality of your RODI but otherwise I would just use it and not worry.

[RubberFrog]

It's strange how we all have different experiences with the same product. Just like our tanks I suppose. Once you find what works for you, stick with it.

[MBVette]

I get it a lot with RC, but have never worried about it.

[STEVE]

Yea...this is my first time with this. I just threw it out and made a new batch....probably not necessary, but o well.

[Origami]

Sounds to me like it's a variety of carbonates and impurities that have precipitated out onto the walls and surfaces. I've even had it happen with IO. When mixing water, if I know in advance that I need to boost magnesium (which I determine from time to time by measuring a fresh batch of ASW), I'll add the magnesium first to my water reservoir and making sure it's dissolved before adding in the salt mix. This doesn't completely stop the precipitate, but it can reduce it some. For the most part, though, I don't worry much about the precipitate in my ASW mixing containers.