I dont have HQis but I have 5x 400w Advance Probe start bare ballasts... I am currently looking for some 250w ballasts to add to my 3x400w that I am currently running..
I just remeasured my tank and its only 29" tall with overflow slots at 27.5" so maybe I won't need 400 watt maybe . I hope this does not dissapoint you I am asking 2 people what they think I should have for this tank and if they say 400 then I will still be looking for sompthing more intence than 250 watt DE HQI .Paul