Residue in 2 part containers

[dartier]

Today I noticed that I seem to be getting some residue forming on the bottom of my 2 part dosing reservoirs. The residue is thin, but covers the bottom of the containers.

The calcium part has what looks to be a tan residue, perhaps precipitated calcium carbonate. I use a bulk anhydrous pelletized calcium carbonate product.

The Alk container has dark brown, almost green precipitate on the bottom of the container. At first I thought it was algae growing, but at the PH of >11, it can not be algae. I use a bulk soda ash product.

So is this just impurities being precipitated out of the soda ash by the high PH (like Kalk does) and a bit of carbonate getting in the calcium chloride and causing precipitation?

Dennis

[disc1]

That is exactly what it is. The brownish stuff in the calcium mix is pretty normal to see. It is normal to see a fine whitish dust in the alk solution. Some of that is just the sodium carbonate falling out as it is very near saturation. But any green color that isn't algae concerns me. Green is copper. Were these solutions made in RODI water or tap water.

[dartier]

Were these solutions made in RODI water or tap water.

RODI. I was worried that the precipitate in the Alk was either a sign the bulk soda ash had impurities, or that my RODI water was not as clean as I thought (even though it shows 0 TDS).

I had another look at the Alk residue. Dark brown. Perhaps iron in the RODI or soda ash?

Dennis

[disc1]

RODI. I was worried that the precipitate in the Alk was either a sign the bulk soda ash had impurities, or that my RODI water was not as clean as I thought (even though it shows 0 TDS).

I had another look at the Alk residue. Dark brown. Perhaps iron in the RODI or soda ash?

Dennis

Maybe. Post a pic if you can. It was just the word green that threw up a flag.

[dartier]

It looks more red in this photo. I placed the jug on a white piece of paper incase the hideous red carpet in my fishroom was tinting it.

https://lh3.googleusercontent.com/-9TNgEnnFc-A/VLIWNtyZWcI/AAAAAAAACPo/ap4oW22v2IM/w480-h853-no/20150111_011853.jpg

Dennis

[bertoni]

That's dark enough that there might be some organics in the mix. I probably wouldn't worry much, though.