Bright yellow stuff on silicone...

[pulpfiction1]

http://www.thefragtank.ca/forum/index.php?action=dlattach;topic=5771.0;attach=10873;image

here's one for sale on this very site,i think its just algae reaction to the cheap compounds in this product,i used my sump well over a year and didnt even notice it after a few months anymore

 

[pulpfiction1]

on a close look at yours,maybe if you had of taped off the seams and made cleaner beads you might not of seen as much,mine was messy and like i said after some time i didnt notce it anymore

 

[MrHermit85]

on a close look at yours,maybe if you had of taped off the seams and made cleaner beads you might not of seen as much,mine was messy and like i said after some time i didnt notce it anymore

Yeah, i bet if i had done a better job it wouldnt look as bad. I ordered the glass slightly too small so I had to be over generous with the silicone. Your sumps silicone looks exactly like mine does, thats a relief! If you were good for over a year then I dont see the problem. I will buy silicone from the LFS or GE next time. If it bugs me too much I will just have to upgrade to a bigger tank and sump lol  ;D.

 

[pulpfiction1]

not my sump but easily as messy as mine was,sump isnt usually on display like mine is and im sure you wont pay it no mind after a bit

 

[Boga]

Thanks for pictures and info. The sealant you used (2031-205) is manufactured by Momentive (Chemtrec). I verified all the data available and it looks that there is nothing wrong with it, compared with other aquarium safe sealants.

These types of sealant contain silica constituents (or variations). Given that your system is in the third week of life and probably you started to have high amounts of nitrates, then I would say that you have diatoms growing on your sealant. Silica is "food" for diatoms and in combination with high nitrates and little bit of light, you got the recipe. Possibly that the silicone grade you used has more available silica and in combination with your aquarium cycle, you got that. Very possible that some diatoms or by-products got into the silicone (diffused into the superficial layer) and coloured the sealant.

Have a look at the following link, scroll down to Brown Algae (diatoms):
http://www.theaquariumwiki.com/Freshwater_algae

I hope this is the cause. In this case you should be OK. Every system is different, and only in certain conditions you have this occurrence.

 

[JordanHurst]

same thing happened to my sump. I used the exact same stuff on both my display and the sump. only the sump stuff has turned yellow the display is still clear. couldnt tell you why, same system different light. no issued over the past 3 years still holding on both sides  :slowclap:

 

[MrHermit85]

Thanks for pictures and info. The sealant you used (2031-205) is manufactured by Momentive (Chemtrec). I verified all the data available and it looks that there is nothing wrong with it, compared with other aquarium safe sealants.

These types of sealant contain silica constituents (or variations). Given that your system is in the third week of life and probably you started to have high amounts of nitrates, then I would say that you have diatoms growing on your sealant. Silica is \"food\" for diatoms and in combination with high nitrates and little bit of light, you got the recipe. Possibly that the silicone grade you used has more available silica and in combination with your aquarium cycle, you got that. Very possible that some diatoms or by-products got into the silicone (diffused into the superficial layer) and coloured the sealant.

Have a look at the following link, scroll down to Brown Algae (diatoms):
http://www.theaquariumwiki.com/Freshwater_algae

I hope this is the cause. In this case you should be OK. Every system is different, and only in certain conditions you have this occurrence.

Thanks Boga, you know that actually makes sense. I also took a closer look at my tank this weekend and noticed that there were traces of these diatoms on my suction cups for my heater and pump too. ( it could be wiped off these areas at least) so that articles description and explanation of diatoms combined with your analysis of the silicone gives a good explanation of the possible cause.

As there have been so many people with the same problem and no noticeable side affects I think it will be safe to leave it be... I am not planning on adding anything to the tank for at least another month so I can still change my mind depending on the severity of the problem at that point. I will also be running GFO at the end of my cycle which should reduce the amount of silica in the tank???( or at least that is from what I understand ...)

Thanks to everyone for you comments, you have been extremely helpful!!!