I mixed 1 tablespoon CSM+B into 250mL of DI. Have been using that to dose my tank between 4 to 6 weeks now. I keep the stock solution in the fridge.

Today I noticed there is a cotton like structure at the bottom of the stock bottle. What is that? Can I continue using my stock solution or should I throw it away and make another batch?

Please help.

Hi Roger,
I have seen this also. Not sure what it is, fungus maybe? Anyway, mix up a smaller solution that will last a week or two and keep in fridge. Personally I would throw out the old and start new.

You can refrigerate the CMS, and/or you can also add some muric acid, HCL.......pool stores sell it

Regards,
Tom Barr

Thanks Chris. That batch with the fungus went to the house plant


Well actually I did refrigerate it. Probably during that 2 months period of taking it out from the fridge to the tank, to and fro, introduced things into it. Just guessing.


Anyway I will just make a small batch that will last for about 2 weeks. BTW Tom, how many drops of muric or HCL ? TIA.

Would this likely also happen if mixed into RO/DI water? (Just curious.)

Hello rusticitas,

I do use distilled and can still get this if the solution sits around to long in fridge. BTW personally don't use HCL, just smaller batches.

Could you also use the acid that comes in the "PH Down" product? I think its sulfuric acid, maybe???

-Mike B-

pH down is H3PO4, phosphoric acid...at least it use to be.......

Regards,
Tom Barr