You need a lot more filtration. 2x Emperor 400 aren't even close. Those HOBs are highly overrated...don't believe the numbers on the box. I'd recommend adding 2 large canister filters.
As for filtration goes I trust it I've kept this same aquarium and filter using it in a marine reef and also a fowlr aquarium and it did what it was supposed to do I've had way more larger fish in this very aquarium before I decided to come back to fresh so idont think that filtration would be much of a problem I've had many large fish not just live but thrive in this very aquarium
Ya im down with that however you will get very little love here. Unless you are planning on keeping a single 4 inch fish in that 150 and running 2 fx5s to keep up with the bioload. Oh and of course you would need to upgrade in a year or so in case it reaches 4.5 inches... Lol not making fun of you op just alot of the attitudes I see on here lately. Take alot of what you hear on hear with a grain of salt. Apparently you have experience in the hobby if it sounds freaking ridiculous it is...
it did what it was supposed to do