Alternanthera reineckii rosaefolia. Best bet for low tech tank color.

[Stan510]

It's surprised me with fast growth from the get go as a gel plant in a bag. Its adapted much better than A.r. rosanervig and THAT I thought was doing ok last year when I planted it..it unfortunately just lost its vigor after 9 or 10 months.
"Rosaefolia" has been even faster and not one stem has faded...my first did lose some stems in adapting to underwater from a bag. No lost leaves either a strong start.
I know many want to know what's a colorful plant for low tech?...this is it.

 

[Wills]

Looks great! The plants that have wound down after 10 months might just need perking up with some root tabs?

Wills

 

[Stan510]

I did take cuttings..but the cuttings of that never rooted and the bare stems just melted. Low tech..lots of fish..might have worn it down. Others have had the same problem.
I'm keeping to low tech..and things succeed. Just don't expect those rainbow vivid colorful to be easy. BUT!..I have watched a vid of an aquarist who grew vivid red and orange plants low tech ,no Co2. He says intense light and lots of iron and he likes a dirted substrate.

 

[Wills]

Some of the red plants do work in low tech but I think you need softer water but like you said iron helps and in some plants low nitrate levels do it too

 

[Stan510]

Also Wills,it came to me..he had Red Cabomba- always said to be difficult, thriving. He posted pruning it. Youtube...but darn if I forgot to bookmark it. An Indian gentleman.
Our water rates a 1 on hardness scale. A little on the alkaline side though with a PH of 8 up to 9.

 

[Stan510]

If I had known the Alternanthera would start so strongly? I would have taken the seedlings and pulled them apart singly instead of into only three clumps. I expected some to die,others to take time to root. Instead,its taken off on moderate bright lighting. I would have gotten much larger coverage of the center.
See? After 50 years..still learning and also still learning that a species plant and its many cultivars can be so different.

 

[Stan510]

It has really grown..far beyond expectations.