Using a Salifert PO4 test kit, I measure the water from my reef tank for Phosphate. The ideal reading is 0 to .03ppm (yes, it should be super low). Over the years, I've seen numbers as high as 3ppm in my tank to as low as 0. For the past 23 months, I've been dosing vodka daily to maintain lower nitrates, and it helps keep phosphate from rising but doesn't omit them like it does for others. I'm sure there are a few factors at play, such as my less than stellar habit of not doing regular water changes to how much food I put in my tank daily to how long my reef has been running... and probably other reasons as well.
For the past few years, I've used Blue Life USA's Phosphate Control. It's easy, not overtly expensive, and knocks them back down to 0 overnight. I add a specific number of drops to my reef, the water gets cloudy as the phosphate in the water turns to a solid (which is why this product is called a flocculant), and the skimmer exports it. I probably tend to treat my tank with Phosphate Control every 6 to 8 weeks, and always at night when my fish are at rest.
Recently, I decided I wanted to try something different. Instead of dripping 120 to 150 drops of the product into my tank, I opted to add 10 drops in the skimmer's reaction chamber, set a timer, then dose again, and again, and again, until I dosed the full amount. The reason for this method was to get a more immediate reaction in the skimmer body where I wanted to export the solid matter and at the same time stop clouding up my tank. I'd heard this is what some public aquariums do, and wanted to try it myself. For this process to work, you need to be home for the duration, which in my case was about 5 hours or so.
Lifting off the collection cup lid, it was simple to drip in 10 drops.
I put the lid back in place, and set the timer for 25 minutes. This time is the right amount to not cloud up my tank - I could wait longer of course, but the point is to complete the dosing that day. Shorter periods would result in a light fog.
By the fourth dosing, it was obvious that the product was working.
I should point out that the cup was cleaned just prior to this dosing, which happens to coincide with when I was feeding my reef. So while some normal waste is also being collected in the froth, the white stuff is what I'm trying to show you. This is Phosphate. (I'm sure some chemistry guru would argue that point, but until they do I'm going to run with my hunch that I'm reasonably accurate.)
So if you'd like to treat your tank but worry about your livestock, perhaps you could try to dose in the skimmer with a lesser amount multiple times one day. Phosphates are exported, the display tank stays clear, and your fish don't have to breathe the flocculant through their gills.
When I tested tonight prior to dosing, it was measuring .03ppm. Tomorrow I expect it will read 0. I dosed 50 drops tonight over 2.5 hours. The timer is key, as it let's you do other things and simply reminds you when it is time for the next dose, then you can get back to reading online or watching your favorite tv show. You might want to keep a note pad nearby to mark down each time you put in that dose, so you won't lose count with all those distractions.