I am seeking advice to see if I should make any changes to my current set-up. This is my first drilled tank. I bought it about a year ago used and made a bunch of changes. Currently the tank is down because there is a spot of white joint so I'm taking precautions. I figure this is a great time to make any changes or upgrades needed. The tank is 180 gallons, acrylic, with a center overflow. 60"x24"x22"tall. I set up a Herbie overflow using a gate valve. I have a wet/dry sump. 1350 gph little giant pump. Finnex heater laying across bottom of return reservoir in the sump. I have a powerhead on the left wall in the tank. There is a bubble wand along the back right wall. I am using pool filter sand for a sand bottom. I have a large piece of driftwood in the center of the tank. I have 2 juvenile oscars (1 albino, 1 tiger), 7 adult silver dollars, 1 common pleco. I plan to get one more fish, likely a blue acara. I feed them frozen food, spirulina flakes and make food from organic spirulina. I use Prime for water dechlorination. I do water changes every 1-2 weeks.
I have some questions/concerns... Mostly around the sump filtration.

I have some questions/concerns... Mostly around the sump filtration.
- I think I have an issue with not enough mechanical filtration... There are 2 square and flat sponges, about 1" thick x12"x12", that lay flat on a tray with holes throughout, causing the water to run through most of the sponge. Underneath there are 5 gallons of bioballs and in the reservoir at the bottom i have 5 large sponges and some lava rock. In the middle chamber i have 2 layers of the same 1" thick foam. In the right reservoir i made a platform from egg crate so i could lay the heater across the bottom and on top of the eggcrate put biomedia. I have 4 bags with ceramic rings, bio balls, biorocks, and a small bag of carbon. Problem is the biomedia in the right side constantly get very dirty. Also on the left side the sponges and rocks are covered with a sludge. Is this good? Should I use other types of media? Should i clean this part of the sump? I clean the 2 flat sponges but not the bioballs or the sponges and rocks in the bottom left side. I do clean the sponges i put in the middle chamber. I rinse out the dirt from the bio media on the right side and try to keep that side relatively clean. Am I doing things right?....
- Someone told me it's better to have the gph slower so the water is in contact with the biomedia longer. Should I turn down my pump?
- Would you suggest I use a different type of bio media?
- Would you do something different? Can i do something better? Cooler?
