Has anyone grown these side by side? Is there much difference between the two?
In most conditions there will be a significant difference between the two
I grabbed a quick (terrible) picture from my tank for you just now
Please excuse the algae and general mess, my tank
is going through something
Like previous posters have mentioned, BR is much more "naturally" red, and does not need nitrate limitation to produce nice red colors.
H'ra can turn very bright red under extremely nitrogen limiting conditions, but to produce such a red is quite an advanced balancing act without having the nitrate limitation get too severe for overall plant growth in the tank.
My tank measured 25 ppm NO3 recently, so as you can see the BR does not need low nitrogen to have a quite red color.
Other differences between the two include a broader leaf on the BR and also a much more upright growth habit.
BR also has a subtly notched leaf tip, you can see it most clearly in the upper right side of my photo.
My tank runs medium light intensity, so BR does not need high light either.
I love the Rotala Blood Red SG, its quickly become one of my favorite plants, and I highly highly recommend it.
I expect it to eventually dominate the market for rotala rotundifolia varieties, given its effortless beauty and ease of care