If your nitrates are staying stable then yes I would keep dosing small amounts of phos until you get a reading. Once you get a reading then go from there to maintain it. A 0.02 phos increase isn’t really enough to worry about. Honestly I’d only increase it 0.01 until you get a reading then maintain whatever level you want just don’t exceed 0.1 on your phosphates. Rock sand corals ect will soak it up till it’s balanced out. Eventually you will get a reading. Just don’t change too many things at one time. Like feeding. Keep your normal feeding schedule. It’s easier to control how much phos is in your tank with the additive then with food.So are you saying I should just continue adding the recommended 2.5mL per day until I get a reading of 0.02? I'm on day 4 of that and it makes me nervous adding so much phosphate into the tank. If the equation on the bottle is correct, this is enough phosphate to be at 0.08 over 4 days but has gotten me nowhere. Which would mean there is some form of phosphate sink absorbing everything I'm dosing. I just added today's dose roughly an hour ago and I tested phosphate and it is still 0.00. The only thing I found that could be the issue other than 2 faulty tests from two separate companies, which seems unlikely, is "In a low phosphate situation, some portion of the added phosphate will bind to calcium carbonate surfaces, lowering the actual amount in the water."