Clear silicon turning redish.

[jason2459]

I haven't seen this before but the clear silicon I used to seal a ranco temp probe is turning a redish color where its in the water. The silicon outside of the water coating the probe is still clear. Its the same silicon I used to build my baffles in the sump, GE I, and that silicon is still clear. I have zero lights on in the sump area as I want a cryptic type zone which I already have some great growths of sponges and other odd this that are flilter feed in just the two months I've been running the sump. I haven't started dosing vinegar yet as I'm waiting on some biopellets to finish their duties which they've done a great job. Phosphates are not detectable and neither is nitrates. I'm sure I have some as I have a small bit of algea remaining which I don't mind and has been kept in check. I haven't had any cyano bacteria in a really long time. The red coloration does not rub off, seems like its on the suface, and seems translucent. That's the best way I can descibe it and all the relavent information I can give unless someone has any specific questions I didn't give already.

So, what is it, why is it not on the rest of the silicone in the sump, and should I worry its actually something leaching out of the probe which is why I coated it in the first place.

Best picture I could get. The flash kind of washes the red out but you can still see it and where the water line is on the probe.



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[jason2459]

Let's try uploading the picture one more time.



Edit: and one more time...

 

[jason2459]

One more piece of info is that the temp prob is in the area where kalk is dripped from my ATO. That's pretty much all I add to my system besides various frozen and pellet foods.

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[Randy Holmes-Farley]

I'm not sure what that is.

What material is the temperature probe?

FWIW, my sump has a deposit on the side where limewater is added. It is clearly CaCO3, but is reddish brown on top and is likely coated with iron or other colored metals. This looks different, however.

I tend to think it is something intrinsic to the silicone that has changed somehow.

 

[Daimyo68]

I installed my baffles using the GE1 silicone also, over a year ago on a brand new system. A few months in, it turned red in one area, a few inches in length.

I haven't had any adverse reactions since noticing the color change. The system has been running ever since then with no issues. I posted this same question a long time ago when it first happened.

Never got a definitive answer, except for the usual "remove it all", "you can't use that" etc type. All good responses, but never a reason for why it happens.

I'm assuming its a reaction with the salt water itself, because I wasn't dosing anything at that time, my temp probe and pH probes were not in the area of the color change.

 

[aleonn]

I used GE1 for sump baffles as well. After a few months they glowed bright green/yellow. A search on RC yielded similar experiences, most citing harmless algae growth. The discoloration eventually went away without harm for me.

 

[bertoni]

I'd guess it's some sort of microbe, but without a microscope, it'd be hard to determine that.

 

[noobtothereef]

maybe because the silicone is sooo thick it is still releasing vinegar ( the solvent in the silicone) and is feeding a bacteria thats growing on it... just a shot in the dark...

 

[jason2459]

Interesting ideas and thanks everyone for the input.

@RHF: I'm not sure what the materials the probe is made out of but Ranco says not to put it directly in liquids and it should either be coated in silicone or they sell a shrink wrap sleeve to go over it.

http://www.etcsupply.com/ranco-etc-1309007044-replacement-sensor-p-96.html

Also, you can also see in the picture where the water line is on the sensor line a brownish deposit as well like you describe. You can also see in the background the drip line for the lime water which is also where the probe goes.



@Daimyo68: Good to know you haven't seen any adverse effect over time. I don't see myself removing it all if it's not effecting anything.




@aleonn: Those are some different colors. I have no lights on in my sump or refugium area so don't think it's any kind of algae.


@bertoni: It would be interesting to find out if it's organic or a chemical reaction. What kind of magnification would be required to see something like this?


@noobtothereef: I did coat it pretty thick but not really any thicker then the silicone on my baffles. Now, with that said I do have one baffle that I really laid it on thick to slide the baffle into as I wouldn't be able to get in between the baffles. I inspected that one this morning and there is in fact some red along the bottom line of silicone. So, maybe it is something with the curing of the silicone. I did let the silicone sit before use for about 5 days.

I couldn't get a clear picture of the red on the bottom but here's a previous picture showing my masterful silicone work. :crazy1:

 

[bertoni]

1000x is fine for bacteria. Even less magnification might show some structure.

 

[Daimyo68]

As mentioned, I haven't had any problems with using the GE1, but did get some color that has pretty much gone away. The only type of outbreak I have had with this system is cyano (battling it now), but it's been 1.5 years since this system first came to life, and I don't believe that the silicone changing color has anything to do with it.

Other than that, corals and fish are happy, fat and healthy.


Just a note on applying the silicone inbetween the baffles. If you do it in the future (which we all do get into bigger systems/sumps), you can use a dowel to smooth out the silicone down in the area's you cannot reach by hand. Run a bead of silicone where you intend on putting the baffle, slide your baffle into the bead, and then use the dowel to get a nice clean seal.

I purchased a 1/2 dowel from HD, and it worked great.

 

[jason2459]

1000x is higher magnification then I have right now. That would be a pretty intresting thing to invest in though and check out.




Daimyo68 thanks a lot for the input. Great idea using the dowel. I didn't even think about it as I really didn't care about the looks considering it's sitting in the dark in my basement. I'm just happy that it's most likely not anything leaching out of the temp probe.