weed control in interlocking brick?

Never heard of magic sand. Seems Google hasn't either, at least for weed control.

Try roundup or similar weed control products. There is a new flavor (new to me anyway) of roundup out that claims to prevent weeds for the entire growing season. I bought some, but haven't tried it yet - so can't comment.

edit----

I was intrigued by your question and found this - http://forums.redflagdeals.com/magic-sand-vs-joint...

Driveway Weed Control

I've seen Magic Sand at Home Depot. It's actually a sealer. It has a resin in it that sets up and seals the cracks once you spray it down to get it wet after applying it to the cracks. It is suppose to keep the cracks sealed for about 2 years which also prevents weeds from growing.

To kill the current crop of weeds, you can spray them with "Ground Clear" made by Ortho. It has a guarantee to keep weeds dead for one year. We use Ground Clear along our back fence and it kills everything. Reminds me of Agent Orange used in Viet Nam. It's good stuff!

THere is something called 'soil sterilizer that you spray into the cracks. Its like roundup but lasts for years.

for some reason bleach comes to mind. Not sure how long it works tho. my dads friend used it in his area.. straigh bleach not that watered down stuff. but he was killing anything and everything that grew in the one area.. he did this prior to laying the brick down for the walk way.

i don't talk to them anymore so I'm not sure how or if anything grew back.