Impulse purchases: worth the splurge?

[ladster]

Today I picked up some random plants for my 500l tank, it's still lightly planted but has loads of artificial decor, and I'm in the process of switching to all natural. I've already got 5 Zorchzon swords and 5 Marimo moss balls, and today I'm adding hornwort, Java fern, and yeah more Marimo moss. I've heard hornwort's a really beneficial plant, so I'm curious - as a floating plant, will the reduced water surface movement affect oxygen levels, or will the plant replace the lost oxygen?

[sSjey]

My experience with hornwort was a mixed bag - it was great when it was under control, but when it took off, it was a real challenge to keep it in check. I used to tie it around some branchy wood to keep it from floating away, but every couple of months I'd have to pull it out and go through it stem by stem, keeping the healthy bits and chucking the rest. The bits that were next to the wood always looked a bit bare, so I'd just snip them off. This process would repeat itself every few months, until I got fed up with trying to separate it from the water sprite, which was also making a break for it. In the end, I had to choose between the two, and the hornwort got the boot. The water sprite met a similar fate a couple of years later, and I replaced it with frogbit.

As for the floating stems, they didn't seem to cause any issues with the fish - they'd just float on the surface, no problem. My current frogbit covers most of the surface, and the fish seem perfectly happy with that.