With practice, care and some skill, you should be able to hover the end of your syphon tube just over the surface of the gravel. It'll then remove the loose waste.
Probably not much help to you now, but when I set up my tanks, I always made sure that there was a slope in my substrate, leading down to the front. This ensures that a lot of any waste will flow 'downhill', to where it's relatively easy for me to remove it.
It could be one of those pretty red plants that are not really aquatic, but that fish shops like to sell and customers buy because they look pretty...for a short while.
Two words...floating and plants.
You still NEED a proper test kit.
Although here in Blighty, our water supplying companies have websites with all that sort of info on it. Perhaps your water supplier has a similar set-up?