In the past, Nitrates always read non-detectable using Salifert Test kit in high resolution mode. Phosphates will normally hover around .06-.08ppm. When phosphates creep up above .08ppm , I normally would add 2 tablespoons of GFO mixed together with my weekly 1 cup of Rox .8 carbon and packed tightly using filter floss. This would bring it back down. I can get it a little further without GFO into the .02 ppm range by tweaking the amount of food. I'm a heavy feeder so when I say reduce food the fish are still well fed.
Since nitrates have always shown as non-detectable, I decided to give KNO3 dosing a try and see if can get phosphates lower without having the adjust feeding schedules or occasional use of GFO.
When running a ATS and your nitrates are not zero then you may need to make adjustments to your scrubber lighting or flow. If that doesn't resolve then your feeding too much or your ATS is just not sized well enough for your system.
I purchase the Spectracide Stump remover for my initial testing and runs about $7.
You can buy in bulk for substantial cost savings and I suspect it is higher grade for long term use. I picked up 10lb bag of 99.8% pure from DudaDiesel.
Mix 1/2 cup of KN03 ( Potassium Nitrate ) with 1 Gallon of RO/DI water.
For my system, 60mil of the solution will raise Nitrate to .2 - .5ppm range.
By the end of the ATS ( Algae Turf Scrubber ) light cycle. Nitrates will be at undetactable levels and Phosphate levels tested using Hanna Checker ULR Phosphorus Checker ( Model HI736) will read 0-1ppb ( < .01ppm ).
Since running ATS for nearly 5 years, coraline algae rarely grows on rocks and never on the glass. Within the first 2 weeks coraline algae was quite noticable on both the rocks and starting to form on the glass.
Coral coloration and expansion. No noticable difference. Never had any complaints on coral coloration prior to dosing and have not seen any noticable difference or pastel colors. I highly suspect corals are still getting some nitrate/phosphate during the day from feeding the tank. When the main tank lights are out and the ATS running it's likely removing all the excess. If I were not feeding daily I might expect to see negative coral reaction.
I do seem to have an increased amount diatoms on the glass and throughout the week some diatoms on the substrate. After weekly substrate siphoning its nice and white again. I'm hoping this will lessen overtime. I have been adding the KN03 in the morning, perhaps waiting until the evening may reduce diatoms on the glass that I have been seeing.
I haven't noticed an increase in the weekly Algae Harvest, it seems to be about the same amount and consistancy. However, the color of the algae is a much darker green.
At this time it is still a manual dosage of 60mil per day with an occasional skip if I haven't feed as much as normal or just simply forget to. I may automate with dosing pump at some point in future but not until I'm fully comfortable with the results.
Unrelated Just for Fun:
Here is a pic feeding the gonipora. Hole in the cap for syringe to add gonipower or any other filter feeding food products. Let it sit for a few minutes to protect from water flow and mostly fish.