Steve comments:
>> My Crypt. wendtii's are growing hairroots _out_ of the substrate,
>> straight up into the water column.
>> Why would that be? The plants are very healthy otherwise.

>Have you disturbed them so that the roots became exposed? The only
>time I have seen C wendtii emerge (aside from being disturbed) is
>to push a new leaf stem out. Could you have aggressive fish?
>Crypts seem to love to have their roots in the soil if there is
>any in the substrate.

This is a an exclusive plant tank (haven't seen any otocinclus recently), so
it's not the fish. And the roots don't seem to emerge, a better 
description would be that the hairroots are growing in the wrong direction. 
There are LOTS of those, yet the big, thick roots stay in the substrate.

in sunny, summery Waterloo