Shipping only specific items with TARE weight?

Ok so here my problem. I am setting up a store with Zencart that sells saltwater aquariums equipment and livestock using the XML UPS shipping module. Most items are easy I can set the weight of coral X to 5 pounds and coral B to 4 pounds just like dry goods.

But, thing I am having a problem figuring out it shipping costs for items that are small and where the quanity of the items does not change the overall weight of the package much past a base water weight. Example given - Snails. Now I can ship say 20 snails for nearly the same cost as shipping two snails as most of the weight of the bag would be water. Lets say the water in the bag weighes 3 pounds. If I set the weight of the snail to say .05lbs it would theen calculate the shipping for the bag at .10 pounds when it is really about 3 pounds. Now if someone were to order 30 the weight would show to be 1.5 pounds.. neither is nearly right. What I am wondering and have in mind is can I set a TARE weight just for certain items somehow. Like give certain snails, crabs or other inverts for instance a starting weight of say 3 pounds and then have the small amount of weight added for quantity which would get me a lot closer for those types items.

Thanks

I am using Zencart 1.3 and the site address I am setting this up on is saltycritter.com/storefront

You would have to write something more customized for helping compute weight ...

You have a unique type of product where 1 product could be the .05lb snail but it needs the 3lb bag of water ...

Then you could throw in the other 30 slugs ... into the same 3lb bag of water ...

Then you add that lionfish at .25lbs but best give him his own 3lb bag of water or ... you wouldn't really be a live fish online shop ... :eek:

What you really need is an individual tare calc based on your packaging that is more specific than a global tare weight ...

Not even the percentage one really works well for you, due to the nature of your business ...

You need to have something customized here that can be more human like in thinking ... who's who in the zoo ... er ... bag?

It could be coded ... but ... you have to break this down more specifically so that coders who do not bag fish all day have a better clue ...

I use to work in shops ... and once was really good at it ... umm ... 20 some odd years ago ... many thought I was one of the best ... but ... alas ... I am a computer geek now ... :cool:

Meanwhile ... back at the pond ... you would really need a bit of custom coding to go along with your shop if you cannot make it generalized enough based on the current methods ...

Thanks for the input on this and the other topic... I figured all the fish and corals would be pretty easy as each would almost always get thier one bag. Just the small inverts that people would buy multiples of are giving me the hard time. Thats why I thought maybe there was a way to add a tare weight to an individual item. Well maybe if I cannot figure something out I will just have to limit it to like multiples of 10 or something of the like