i have to admit looking over your specs that you may want more filtration. This was something hard for me to grasp when I started out 4 years ago, but the most important part of filtration is the bioballs (or rings) for the beneficial bacteria. The general rule i have always followed is that i run filtration that is rates 2 times higher than what it says on the box. Example for your 90, i would find something that is rated for at least 150 gallons if its a HOB or a large canister like eheim or fluval rated around 90gallons or more.
I may help prevent issues for you later on. Other idea would be to slap on another aquaclear 110...
-Just another day in paradise-