Urgent Water Change Help

[snorkeler]

Hello, I need some urgent help...

I mixed up a batch of salt water for 40L two days ago in a dark blue Rubbermaid 68L container which I left covered with a powerhead running inside. Red Sea salt, added in a weight proportion to reach 35ppt. Also added 2 tablespoons of Alk buffer.

Today as I opened it to do the change I noticed stuff floating on the water, all over the surface. Thought it was strange and decided to test the water. Everything normal (params below) but my pipette got coated with something brownish. Same for the inside of my test tubes. Not too coated, just slightly, and in the tubes it seemed a little powdery.

I cleaned the outside of the pipette on a paper tower and it seems like a brownish powder.

I used the same container to remove the used water in my previous PWC about 2 weeks ago. I did clean it with freshwater afterward, but could it be that spores of those brown powdery things that keep growing on the glass (forgot their name) resisted and grew in the new water. This water got no light, for the Rubbermaid was covered and it is dark blue....

Is this normal, should I be worried, may I use this water to do the PWC in your opinion? If not, if it is likely something survived from the previous change, how do I clean the Rubbermaid so this doesn't happen again?

Thanks! snorkeler

[snorkeler]

Oops.... just noticed I forgot to post the parameters of the new water batch... they are:
S.G.: 1.024
pH: 8.4
Alk: 2.9 meq/L
NO3/4: 0
NO2: 0
NO3: 0

All totally normal. I was expecting to get some Amonia, but after that read zero I felt more confident that maybe this water is safe.

[WethandsCT]

Alk buffer and new saltwater do not mix, my Alk buffer is for RO water only. Slime coat is pretty normal.

[IslandCrow]

My guess would be the alkalinity buffer as well. I'm guessing adding it to salt water that's not completely mixed may have caused some sort of precipitation. If that's all it is, I would think the water is still fine to use, but you may want to ask in the Chemistry forum and see if Randy, Boomer or bertoni (or any of the other experts there) have any thoughts. Is this the first time you've added buffer to your saltwater mix, or have you done it before with this particular salt?

[snorkeler]

Yes, I did add Alk buffer to new saltwater before, but I added only one tablespoon and after about 1 day of mixing. This time I added it straight with the original salt. I'll try posting in the Chemistry forum, good idea. Will call off the WC for today, too late to start.

Thanks!

snorkeler

[Chris27]

Be careful with the Blue Rubbermaids - they can be made with recycled material which can leach phosphates and possibly other chemicals. The Grey brutes are a better choice as they are classified as food safe.

[bertoni]

Some salt mixes start at a high pH, and adding alkalinity buffer might push it over the precipitation point. Unless the salt mix is deficient in alkalinity, adding a buffer is not useful. I'd check the pH before dosing, in the future. There also might have been some contaminant somewhere in the salt mix. I wouldn't worry all that much, and I'd likely try the salt mix.

Wiping the container with a cloth and vinegar should be fine for cleaning.

[snorkeler]

For those reading this thread in the future with a similar problem, here goes the end of this story:

I waited another week and a half before using the water, left it without circulation or light (rubbermaid closed). The water looked exactly the same, didn't smell bad, had pH 8.4, Alk normal, Amonia, Nitrites and Nitrates zero, so I did the water change.

And all went well.

snorkeler