Sorry for all the messages, there's a character limit on here that I was unaware of. Just start with the bottom message and go up. Each new message is a different paragraph. Oh, one last piece of advice is to use masking tape to get a good clean edge on your silicone. On the sump just place a tape line a quarter inch or so on either side of the location in which you plan to place your silicone bead. Pull it out immediately after you smooth the silicone out. Finally, remember to have lots of denatured alcohol around to wipe yourself and all your tools clean. Silicone has a nasty habit of getting on EVERYTHING. Consider this my P.s. . Hope this helps, if you need anything else just give a hollar.
If I remember I will email you a picture by Monday just so you can see what the product looks like. After having nearly killed my fish, taking out all my coral, and killing a beautiful black and orange sea urchin I take this topic pretty seriously. To me the extra price of the Momentive silicone was well worth it. Also, if you're in doubt you can look in Reef Central's DIY forum. They are very adamant about its use over there and often hound people who say they are using anything else.
Happy sump building!
Now for the bad, you can't just go out to Lowe's and buy this stuff. If you have an industrial supply company near you, you might luck out. However, you can order the silicone online at McMaster.com. As an engineering student I order stuff for projects here all the time. You pay a bit more for their products, but they ship to you fast and they have excellent customer support. I ordered my Silicone from them, had it shipped UPS ground and it came the next day!! However, I paid $34 in total for two cartridges. The Momentive RTV 100 Series silicone is more expensive to begin with, about $7-$10 per 10.1 oz cartridge instead of $4-$5, but Mc Master is on the high end of that and you still have to pay shipping. Maybe you can find it cheaper, but if not, here's their web address [/url]www.mcmaster.com[/url].
Yesterday I just finished rebuilding my sump. I used Momentive RTV 108 which is the clear 100 Series silicone. Formerly this product even said that it was aquarium safe, but after Momentive bought the product from GE they quit advertising that way (legally they now say the product can't be used underwater). When I called Momentive to ask for their advice on using it they told me that, although for legal reasons they could no longer recommend the RTV 100 series for aquarium use, they could tell me that aquarium manufacturers still use it and that the formula hasn't changed since GE used to advertise it as aquarium safe. Additionally, once fully cured the Momentive RTV 100 Series silicone is FDA approved for use in long term food contact. It actually meets a higher FDA food safe standard than the GE I.
Just thought I would take the time to message you about sump building. My suggestion is to use Momentive 100 Series silicone (103 is black and 108 is clear). You can use GE I as it is FDA approved for use in long term food storage; however, it is not an adhesive silicone. That means the baffles closest to your return section may fail due to shear stress loads that GE I were not meant to handle. The Momentive 100 Series Silicone is rated at roughly 400 PSI for tensile strength and about 40 PSI for adhesive strength