Dark Red/Brown Slime in RO/DI water bucket and in salt water bucket

[ekrunch]

I've got some dark red/brown slime that has formed in the bottom of my RO/DI water output. It has also started to form in the bucket we use for salt water and i'm starting to worry.

I wiped out the RO/DI bucket a week ago but the slime it back again. Does anyone have any idea what this might be and how to get rid of it? The RO/DI is a new unit as of August and has been producing great water... apparently up until recently that is.

Should I use some sort of chemical to clean the bucket out instead of just a rag and water? I'm afraid to use something that might cause issues with my water and harm my tanks later.

Thanks,
Ed

[bertoni]

I'd check the TDS of the RO-DI water. The DI resins could be shot if they haven't been changed. I'd just wipe the bucket to clean it, or perhaps use a bit of vinegar on a rag.

[ekrunch]

TDS is 007 and my tap is in the high 300's. I suppose I could probably use a new DI if i've been running since August and have done many water changes... plus the 150g it took to fill up my latest tank. :)

[bertoni]

Hmm, 7 isn't that bad. Hard to say, though. I'd try a new cartridge, but that might just be money down the drain. RO-DI shouldn't have enough nutrients to suport much growth. Any chance of the reservoir being contaminated some way?

What's the TDS after the membrane but before the DI?

[ekrunch]

There is definitely a chance of the reservoir being contaminated. I'm not sure how, but who knows... I think it's time to get in there and clean everything really good. I think tomorrow's job will be to remove all water from my fresh and saltwater containers (Brute trash cans) and then get in there with some vinegar and clean that thing out!

The TDS after the first 3 stages of filter and RO but without the DI is 25. Is that high?

[ekrunch]

Also, I checked the instructions for my RO/DI (Reefkeeper Typhoon III 75gpd from airwaterice) and my DI is the color changing type that turns from black to orange. Mine is still black so I suppose that's a good thing. The manual also says to change it when TDS hits 15.

[bertoni]

25 TDS after the membrane is rather high, if that's a 75 gpd (or less) membrane. Still, the membrane is working at least reasonably well.

The color-changing resins are a lot less precise than the TDS meter. When to change the DI cartridge is open to some interpretation, but when the TDS is starting to rise, it's because the DI stage is releasing ions, possibly including ammonia and similar unpleasant ions:

http://www.reefkeeping.com/issues/2005-05/rhf/index.php#7

[ekrunch]

It looks as though my Phosphate tests may have bitten the dust. After further study and more Phosphate testing, the results appear to be constantly high. Considering how little I use that test, it has probably passed it's shelf life. I'm going to take some RO/DI water and some tank water from both tanks down to the LFS and have them run the tests on it. Maybe i'll find out that I just didn't wash much bucket out well enough lately.

I also took out my Freshwater collection bucket and have some white vinegar and water running through it via a MaxiJet. I'm going to let that stir for a while longer and then scrub it out really good. I'm going to do my saltwater bucket tomorrow and try again. I'm now wondering if I just didn't clean out the bucket good enough when I bought it.

I will also contact the vendor of the RO/DI and see if they can be of assistance with the high TDS levels from that membrane. I could be off on my water pressure or temperature or something.

Thanks for all of your help so far!