First time in coco. SLOW growth...please HELP!

Hello,

I recently switched from soil to coco coir and I am finding it's growing really slow. I'm growing in a 3' x 3' x 6' tent with a 400 watt MH/HPS bulb. I'm currently saving up for an inline fan/filter combo, so I keep the tent flap open to exhaust the hot air for now. My temps are around 26-28 degrees celsius.

I am using the Humboldt Nutrients line: Micro, Grow and Bloom, as well as General Hydroponics Cali-Magic and a heavy duty root booster at half strength.

As you can see, the strain is AK-48. It broke the surface about a week ago...does this look like normal growth? It seems really slow! What am I doing wrong??

Thanks guys.

Here's a closer up shot. Seems to be some discoloration on the girl on the right as well...

Looks about right for a week old.

Looks like you might need to move your light closer if you can.

Okay cool thanks for your help.

It looks like the plant on the right may have got light burned.

They don't really seem that slow bro. It does always feel that way when you start something new especially if you don't have anything in the flower room ahead of it but once the root zone gets nice and healthy they really take off. Give em some 1 3 1 or something of a similar ratio to get those roots kickin and you'll have bushes before you know it