Silicone for aquarium

[Ramon84]

I was told I could use any 100% silicone for a fish tank could I use this wanted to make sure before purchasing

 

[Ramon84]

Hmm… I’m not sure if it was in 52 weeks of reefing… maybe a video on DIY? Or possibly just a video on sumps?

Okay I’m gonna check them out thank u

 

[redfishbluefish]

Not too long ago I read of an incident where acrylic baffles swelled and cracked a glass sump. It was here but I can find the post now.

Interesting! This is the first I’ve heard of that!!

Yes, acrylic does oh-so-slightly swell in water, but it's not much. It's the reason I leave 1/16 or so of an inch on each baffle. I've build my fair share of sumps and never had an issue with them swelling to the point of breaking a tank. However, I do notice it in acrylic covers I make where the bottom only is exposed to water and the acrylic "warps" as the wet side swells while the dry side does not.

 

[TangerineSpeedo]

I wonder if it has more to do with the difference in temperatures, than an actual ingress of moisture?

 

[UncommonSense]

I wonder if it has more to do with the difference in temperatures, than an actual ingress of moisture?

I think the difference in thermal expansion rates between glass and acrylic are part of it, but moreso both the temperature difference, and humidity…

I have experienced the warping aspect of acrylic when I made 3/8” thick acrylic tank lids, with a perimeter and center spine of 3/8” thick, 1” tall acrylic strips welded on… they progressively bowed/became concave over a year or two, on-edge strips and all!

 

[redfishbluefish]

I wonder if it has more to do with the difference in temperatures, than an actual ingress of moisture?

No, it swells.