why cant i grow chaeto
 

i have a 33g sump and a 40 w led light i have about 8-9 mangroves growing nice but my chaeto will not grow whats up, i have a lot of rumble LR in the bottom, take been running for 7-8 months good water par any help

You probably have low phosphates. Algae a feed on phosphates.

Mangroves do too. Maybe they are out competing the chaeto.

stuff likes flow. Started my 20g fuge just by branching off a drain, maybe 200ph got some growth. Added a 300gph power head and growth rate increased.

What's your bioload? Cheato needs nitrates, phosphates, light and CO2 to grow. Any one of these can be a limiting factor. The mangroves have the "aerial advantage" by having access to air (CO2) through their leaves, so your water may be low on CO2.

Do you have any nuisance algae in your tank?

It needs water flow imo. Mine seems to take a break now and then, don't know why, then starts growing quickly again.

Mine hasn't grown at all in since I first got it. Which is abouts 9 months ago. Using 6500k flood lights advised by reefers here

my bioload is very light

You need nitrates and phosphates to grow Cheat welcome to the club your on the right track to keep your SPS happy.

It won't grow unless it has food. But the good news is you should be able to grow SPS...

I got a few decent size turf algae patches in spots around my tank. Y then won't my chaeto grow but unwanted algae is