I agree with ponigirl about seahorse. I am a huge fan of the Aqua C brand of skimmer. Tey make a HOB skimmer, the Remora, Remora pro, and urchin. I have had the Remora & just got rid of it when I set up my 120 and got a bigger style. The day I took it out of the tank to sell it, it pulled just as much junk out of the water as it did from the first day that it was broke in.
So what all do you have in your tank right now? I saw the LS part, but dont mention about anything else.
PH is way low. Nitrates should go down on their own, with LS you will tend to have lower trates also, because CC seems to be hide detritus, and consequently will have higher trates unles when you do 20% water changes regularly and vacuum ALL the CC.