I heard Red Sea test kits are pretty accurate. API test kits are pretty much for when you have your cycle..unless you don't mind getting inaccurate readings and possibly losing corals, inverts, fish, etc.
And you can just use a siphon, but I recommend getting a smaller one than what it's rated. All it would be good for is siphoning out debri on rocks and on the sand. Or you could ditch that and get a turkey baster (or powerhead which is more efficient) and blow off the debri from the rocks and let it be carried down to your sump through a filter sock or something.
I use a felt filter sock and it's made the water A LOT clearer and cleaner, but it does get dirty fast. I put it in the washing machine w/ no detergent and pre-rinse before hand each week when I'm doing water changes and maintenance. Mesh ones dont get as clogged so fast. However, one time, a snail fell into it, died and decomposed and made the whole water smell horrible. I only found out there was a snail after I washed it b/c the sock was too dirty to tell if something was in there or not.
+1 on the GFO
reactor (a carbon reactor would be nice too). It's chaeto morpha, the only macroalgae that doesn't go sexual. It absorbs nitrates and you can just rip it off and toss it or give it away.