I'm not really sure if that's considered a fert to more experienced hobbyists or not. I wouldn't think so but in a way it kinda is.Thanks any help is super greatly appreciated! I feed the otos zuchini overnight everyother day so I think theyre okay. As far as ferts go im dosing Seachem Flourish Excel if thats even considered a fert? But the filter is fairly old so I dont blame you! Marineland doesnt even make the 170 anymore.