Branching hammer

I bought 6 head branching hammer when it was in the store the tentacles were fat and 2 inch long in my tank they r thin but the same length so why r they thin ???

They are in shaded area if i put them under the leds near the elegance and bubble they become worse and extend max one inch so what can i do to make them fully extend ?



Phos 0.08

Nitrate <1

Alk 11

Mag 1460

Cal 450

I feed zooplankton every 2 days