Any idea on my coral?

Alright reef tankers. I need some help. I've had my galaxea for about 2 months and my torch for about a month. But neither one ever extends out fully. Maby a 1/2 inch at most during the day but not at night. My real question is why do both I those corals retract into their skeleton when I turn the lights off and about 30 minutes later they come back out but short still. One head died over the past week on the galaxea but it was technically a 1/2 head since it was cut when it was fragged. All my parameters are as follows:

Sg:1.026

Nitrate: 20

Nitrite: 0

Alk: 220

Ph: 8.0

Temp: always 79

Lighting: T5 coralife light with 2 whites 2 blues and 2 LED moonlights

Lights are on for 9 hours a day

2 powerheads one random blowing the other is fixed.

I have a HOB filter that I clean every Sunday. (Should I ditch this?)

35 lbs of live rock

25lbs sand

30 gallon tank

Weekly 3 gallon water change



Livestock are as follows:

1 cinnamon clown

1 blue damsel

1 six line wrasse



1 serpent star

Several micro brittle stars

3 blue legged crabs

Several snails

1 Peppermint shrimp



Green star polyps (spreading like weeds)

Button polyps (also spreading like weeds)

Green mushroom

Torch

Galaxea

Short tentacle plate coral



Everything else seems to be doing awsome but those 2 corals. Their placement is on the bottom and with moderate to low flow