who is is dong the sump for you? i have had glass sumps and acrylic. I soooooo much prefer acrylic as I dont have to worry about cracking it taking out my skimmer for cleaning or doing regular work in it. I got my acrylic sump from glasscages and couldn't be happier.
I have an acrylic sump right now that i got from glasscages. I paid almost $400 for it. 5 Months later, cracks everywhere :hmm3:. I thought it was a poorly built sump until i did more research on acrylic and found out that overtime, the chemical stress of alkaline solutions cause breaks in the molecular bonds, causing a chain reaction which then cause the acrylic fibers to crack.
This is research article from the
Department of Materials Science and Engineering, Massachusetts Institute of Technology.

The article stated that high temeperature caused acrylic to crack faster. Salt solutions cause less than 7% shrinkage in acrylics fibers. But even if you get a tiny little scratch, it causes a chain reaction which will eventually lead to a crack, especially the areas that already experience physical stress,(in our case) the baffle joints and bent corners of fish tanks or sumps. This doesn't happen with glass.
here is the link to the MIT article "
Chemical stress cracking of acrylic fibres". Its in pdf format.
http://www.springerlink.com/content/h313150623t02017/fulltext.pdf
Acrylic is not as durable as glass. It's more reactive to chemicals and cannot be cleaned as well as glass. Acrylic is stronger than glass and can appear to take more abuse initially, but the cost, reactive nature of it and long term issues are not something i want to deal with.
Im never going to have a fuge so i dont have to worry about rock breaking the glass. All im gona have in there is a return pump and skimmer which are both padded to reduce noise so they dont even touch the glass sump.
+i have a 30 gallon glass tank, i must've beat the hell out of this thing the last 2 years, not a single leak or crack.
Im getting the glass sump from glasscages.