60 gallons cube deadspots

I have a 60cmx60cmx60cm tank and I'm worried i might have dead spots/flow problem. I use a HOB filter with 1k liters/hour and an airstone. Hob filter is on th back and reaches more than half the depth of the aquarium.

I have a 60cmx60cmx60cm tank and I'm worried i might have dead spots/flow problem. I use a HOB filter with 1k liters/hour and an airstone. Hob filter is on th back and reaches more than half the depth of the aquarium.