extruded bafles=leaky sump?

[rtbm]

I posted this in the equipment forum and diddnt get alot of feedback so I figured I would try here.

A good friend of mine discovered today that his sump of over a year sprung a leak. I took a look at it and sure enough aside from a considerable amount of water on the floor it undeniably appeared to have happened right where one of the baffles was siliconed to the bottom. It was extruded acrylic and I am aware of extruded's absorbing properties. What I am unsure of is the amount of time it would take to actually absorb enough water to grow enough to cause a leak in a glass sump? The acrylic was 1/4 inch and was cut almost tight but not snug. The sump went leakless for over a year. If not the acrylic "growing" any ideas what may have caused this?

[RandyStacyE]

So you're saying that your friend 'built' a glass sump without siliconing it at that point, used acrylic baffles and then siliconed the sump with the baffles in place?

If not then it shouldn't have anything to do with the baffles at all. Likely it is just a silicone failure in the glass sump where glass meets glass. This should be the case if the acrylic baffles are merely siliconed inside of a glass sump after the glass sump was purchased or constructed.

[rtbm]

No, the sump was a 40 gallon breeder we just siliconed the bafles into place. I even ground away The corners of the bafles that went on the bottom so that the acrylic would not touch the factory silicone at all.
I didnt want to believe it either but the water was clearly dripping right where the bafels were siliconed. I would be happier to hear that it was more likely a fluke rather than expanding acrylic.

[RandyStacyE]

Oh I get it ... you're thinking that the acrylic swelled and failed the main silicone seal.

[Acrylics]

*much* more likely a fluke. Extruded will absorb 1.6-2% of it's weight in water but will not swell even close to that much. Remember that acrylic is porous and those "pores" hold the water rather than the acrylic itself swelling that much.
All water absorption is complete in about 12-14 weeks so any problem that this effect *could* have shown would have resented itself long ago.

HTH,
James

[rtbm]

thanks. That is closer to what my understanding was. I made my sump almost the same as his and it has been running considerably longer. I will call it a fluke and stop worrying about mine.