I agree with this completely. and i know marc personally, he loves to help!Its fine to build your sump out of acrilic(many do) but you cant seal it with silicon, for that you want a acrilic glue. Like weldon. please google weldon # 16 acrilic glue, iv used this stuff and it works great. Your gunna need some help building your sump, pretty advances stuff, i sugjest you spend a good amount of time reaserching and have a good design ready when you plan to build. I highly recemend this website for building acrilic sumps. www.melvesreef.com You can email him and he can help you out, i would sugjest building one exactly like he does.