I Need Help! Acrylic Glue?

I'm making an acrylic r/o water tank for my auto top off system. Tank hold about 3.5 gallons of fresh r/o water. I have been sealing it with aquarium safe silicone but it keeps leaking. The tank is too narrow for me to fit my arm down in to squish the silicone in very good. Is there some kind of aquarium safe acrylic glue or epoxy I can use to assure this tank dosn't leak a drop? Thanks.

 

Weld on 4--Followed by weld on 16 (Weld on is the brand)
http://cgi.ebay.com/IPS-Weld-on-4-S...emQQptZLH_DefaultDomain_0?hash=item4a9c148c71
http://cgi.ebay.com/IPS-WELD-ON-ACR...QQ_trkparmsZalgo=MW&its=C&itu=UCC&otn=5&ps=63

 

Here are some instructions on how to bond---refer to the capillary method.
http://www.tapplastics.com/uploads/products/pdf/pb02.pdf

 

Thanks for the quick replies guys. This project has been driving me nuts. No matter what I did the silicone would not effectively seal up my water tank. I never knew that silicone dosn't bond acrylic. Thank you very much. I'm getting some weldon and finishing this thing.

 

Just ordered weldon #4 and #16. Thanks again guys.

 

Weldon is awesome stuff. Just got done glueing my acrylic together. This stuff is way cleaner to mess with than silicone. It bonds almost immediately and after applying weldon #16, my r/o water tank is leakproof finally.

 

any pics?