the ph level according to the sensor is 7.4. but the ammonia one is blue which is toxic.....man o man. google search says to do a 50 or 75 percent water change to lower the ammonia. should i?
Yes, as other members have also advised.
do i rinse out the filter with the water i take out?
Yes. The brown gunk is organic matter, and you want to keep this minimal. The nitrifying bacteria live on the filter media but will not come off with just rinsing in a bucket of tank water.
i use the primer concentrated conditioner. says it detoxifies ammonia, nitrite and nitrate. i use it once a week. should i clean bottom and do a water change? or should i just use some conditioner?
Prime "detoxifies" ammonia, nitrite and nitrate, but only temporarily, about 24-36 hours according to the manufacturer, after which any of these three remaining again will be toxic. This is why water changes daily are better. Do not use Prime as a "fix," only at water changes.