I believe you will have problems with keeping these fish in ten gal tank. Cichlids and plecos are messy fish that produce a lot of waste which =water quality problems. They need plenty of filtration and larger tanks are better able to dilute toxins than smaller tanks. These fish would in my view,do better temporarily in large rubber maid tub with heater and filter.
When filter pads,cartridges,sponges ,etc become dirty ,,swishing them around in old aquarium water that you take out during weekly 20 to 25 percent water changes will clean much of the dirt from them. You should in my view replace filter material only when it literally begins to fall apart to preserve the bacteria needed to break down the waste produced by your fish. As stated, your fish are messy eaters that can and do produce lot's of waste and this no doubt is causing filter material to become filthy as you have observed.
You do not say what type of cichlids you are keeping but unless they are dwarf cichlids,, they will not do well in ten gal and I would seriously consider the rubbermaid tub until you can get larger tank.
In the meantime,, Were it me,(and it ain't) I would feed these fish small amounts of food once a day. If they don't eat,, then use gravel vaccum or turkey baster to remove the uneaten food and try again the following day. This will help keep water quality from deteriorating too quickly which leads me to next recommendation. Change approx two gal of water from your ten gal every couple days until you can get larger tank or container. This too will help with water quality.
And lastly,,, Get yourself a test kit such as API freshwater master kit so that you can keep track of water quality which is imperative for keeping fish healthy. If you cannot afford a test kit right now,, then ask fish store if they would test your water for you and ask them for numbers on results. Don't accept their word that levels are fine,or good. If ammonia levels and nitrites do not read ZERO then water changes are necessary perhaps,,, daily until the levels indeed read zero. NitrAtes for your fish should be 20 or below. Some will say otherwise but cichlids in particular, don't do well with NitrAte levels higher thasn this in the long term. If fish display abnormal behaivor such as not eating, gasping at surface ,or rapid breathing, clamped fins,or seem lethargic. Then perform the two gal water change as recommended then test the water twelve hours later. If levels of ammonia,nitrites,or nitrAtes are still high,, then perform another water change. Hope some of this helps.
