Nitrate Police

So my sketchy water tests are concerning me that not only are the nitrates in my 5-gal high, but my 30-gal are getting up there. I was hoping the plants would be using up most of the nitrates, but I'm afraid that's not going to cut it. I did a big water change on the 5-gallon and maybe a 10-20% water change on the 30-gallon. The 5-gal still read higher than I wanted, and I didn't test the 30-gal again. I'm hoping to find a better, more reliable way to test it.

You can see (or cannot see) from this "nighttime" shot (look how the flash picks up the neons and albinos) that the place is getting really overgrown. To remedy that (and give me something else to worry about), I've taken a couple of cuttings of hornwort and anchored them in the 5-gallon with a lead wrap. The 10-watt lamp is only 2 watts/gal, but then again, there's no CO2, so maybe it doesn't need anymore light than that. Anyway, I switched the LED timer to the lamp and we'll see if we can't make something grow in there. It's worth a shot. I'll have to start throwing away cuttings pretty soon at this rate...