# Is a silicone with fungicide ok to use under tank lid but out of water?



## DaveWatkin (29 Oct 2020)

As per the topic. I want to stick an extra light to my tank lid with silicone and I have plenty of bathroom sealant but no aquarium. To save the cost can I use bathroom as long as it doesn't touch the water?


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## Nick potts (29 Oct 2020)

If there are any risks of splashes etc (in fact if it is near my tank water) I wouldn't want to use it, you can pick up the little tubes of aquarium silicone for a couple of £.


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## dcurzon (29 Oct 2020)

there's a tube for sale in the for sale section


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## RudeDogg1 (29 Oct 2020)

Yes I have a tube of marine grade aquarium sealant for sale


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## Steve Buce (30 Oct 2020)

I wouldn’t risk it


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## not called Bob (9 Nov 2020)

I used PU18 it was under £5 a tube and has no fungicides etc, its used a lot on koi ponds and marine setups as a cost effective and safe adhesive


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## ian_m (10 Nov 2020)

DaveWatkin said:


> I want to stick an extra light to my tank lid with silicone


Silicone is not actually a glue. Almost guaranteed to not stick, eventually, especially on most plastics.

If I was adding an extra light, I would bolt it into place, either plastic, but UV resistant, bolts or stainless steel. Then seal with silicone to stop water getting in places it is not wanted.


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## DaveWatkin (10 Nov 2020)

Thanks. I actually ended up gluing some spare heater suction cups I had to the lid using seachem glue (forget the name, flourish something?) and the light clips into them perfectly 

Turns out I don't think I even need the light now anyway, after more research I think the stock will be sufficient and the extra one will just cause me issues of having too much light .


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