For those "complaining" of brown scum with IO

[s_kelley]

Google the problem - search - Brown Scum in Reef Crystals salt water - and you will find the reefkeeping magazine article that I believe explains this "problem" I use RC with RODI 0TDS in Brute Barrels and have the same experience, worsening after the initial mix. I add salt to a full tub of water and then heat and mix with a powerhead overnight and then shutdown until needed. The night before I plug in heat and pumps again and do a change. I think Randy's experiment and pictures in this article explain the precipitation of CaCO3 that we see. He didn't do a full blown experiment with independent replicates or anything rigorously scientific but he did use some nice chemist CSI techniques. I am a biologist and this article reminds me of college chem labs. So, in a nutshell I am fairly certain it is as Randy describes. Here is the link. Basically, it boils down to solubility of the salt mix components and the proportions that the mix manufacturer uses. Some are probably better than others but they are all basically the same... they are not NSW. If they were like NSW this stuff (scum) would be rare.

http://www.reefkeeping.com/issues/2005-07/rhf/index.php

Great read. Not too boring and a great description of things we all should pay attention to as aquarists that play chemist with live creatures as part of the experiment.

Good post, thanks!

 

[rfkeeper55]

red sea coral pro and D+D H2o salt are both harvested from the dead sea area,they are known to be high in organics such as phosphate.
If AWT results are accurrate then phosphate/ nitrate in I/O are high also.

If you leave your salt in the mixing barrell for a while before use and the buildup gets worse i would say its definitely nutient driven

Just wondering, are most brands harvested? or synthetic? does anyone know which brands do either.

Thanks