That will work for repairs but it's messy and not the strongest. For a good repair you usually want to locate the crack/leak, and then apply an acrylic patch over it. Using weldon #4 will come out better and be stronger, #16 is a bit easier to work with if you've never tinkered with acrylic before. You will need to take the leaking sump off line for at least a day so you can dry it out, make the repair, and then let the solvent cure.
You can get either weld on product at jfreeman in boston if you want it in a hurry. If you go with #4 you will want to get a needle applicator to go with it, and check the date on the bottom of the can, don't buy it if it's over a year old.