Live phyto dosing causing P04 to go up?

[BluesClues]

I’ve started to culture my own live phytoplankton in 1 gallon jars and a air stone I add 3/4 of 30PPT salt water and the rest with a left over culture and add 6ml F2 fert and harvest after 10 days. I was dosing 30ml of my live phytoplankton in the am and 30ml at night on a 120 gallon LPS system 4 month old. I started to notice my P04 increasing slowly even with water changes and only feeding frozen PE mysis. I notice my P04 starting to creep up so I stopped dosing the phytoplankton culture and suspected my F2 fert I got from my LFS was funky and I may have dosed to much. I completely threw out the culture bought brand new phyto and F2 and didn’t dose for 10 days or so while I let it cook. The P04 was stable during this time so I thought I figured it out but when I started to dose again I notice it increasing again. I was only dosing 60ml at night before the lights turned off at this point but yet again P04 increased. I thought maybe the phyto wasn’t getting consumed in time, so I dosed it in the afternoon right as the lights turned on hoping the phyto would need to photosynthesize and consume some of my nutrients. Yet again it slowly went up even did 5 gallon water changes each day. So I dosed 90ml live phytoplankton for four days right as the lights turned on and my P04 jumped from 0.26 to 0.36. If anyone had any tips I like to dose the phytoplankton for my filter feeders and keeps my pod populations up for my copper band, possum wrasse and mandarin. For filtration I have a Smart roller mat M, Nysos 220 skimmer (24/7), and a refugium on 16 hours a day. My thinking is even if I over doses the phyto my filtration would be able to remove the phyto that didn’t get consumed before it started to break down and the F2 fert would be the culprit?

 

[BluesClues]

 

[MnFish1]

I’ve started to culture my own live phytoplankton in 1 gallon jars and a air stone I add 3/4 of 30PPT salt water and the rest with a left over culture and add 6ml F2 fert and harvest after 10 days. I was dosing 30ml of my live phytoplankton in the am and 30ml at night on a 120 gallon LPS system 4 month old. I started to notice my P04 increasing slowly even with water changes and only feeding frozen PE mysis. I notice my P04 starting to creep up so I stopped dosing the phytoplankton culture and suspected my F2 fert I got from my LFS was funky and I may have dosed to much. I completely threw out the culture bought brand new phyto and F2 and didn’t dose for 10 days or so while I let it cook. The P04 was stable during this time so I thought I figured it out but when I started to dose again I notice it increasing again. I was only dosing 60ml at night before the lights turned off at this point but yet again P04 increased. I thought maybe the phyto wasn’t getting consumed in time, so I dosed it in the afternoon right as the lights turned on hoping the phyto would need to photosynthesize and consume some of my nutrients. Yet again it slowly went up even did 5 gallon water changes each day. So I dosed 90ml live phytoplankton for four days right as the lights turned on and my P04 jumped from 0.26 to 0.36. If anyone had any tips I like to dose the phytoplankton for my filter feeders and keeps my pod populations up for my copper band, possum wrasse and mandarin. For filtration I have a Smart roller mat M, Nysos 220 skimmer (24/7), and a refugium on 16 hours a day. My thinking is even if I over doses the phyto my filtration would be able to remove the phyto that didn’t get consumed before it started to break down and the F2 fert would be the culprit?

First double check your test - and be sure they are accurate. Second - Phyto contains phosphorous - and as it dies and grows you can see fluctuations - especially if adding as food - and using a fertilizer. The faster it grows the faster some of it dies off - and that might explain what you're seeing - and or - since you're adding more - you're also adding some of the fertilizer from the mix. Is there a specific reason you're adding it in the first place? If so - my guess is that constant (i.e. stable) additions as compared to variable additions will even out PO4 levels.

 

[EnterName]

When phytoplankton is consumed only a fraction of the bound phosphate will be used by corals and filter feeders for growth so it stays bound to biological matter in the long run. A significant amount will just be consumed, broken down, and released back into the water sooner or later.

To actually get rid of phosphate you need to take something out of the tank that has phosphate in it. Water changes, macro algae, and adsorbers are the more obvious solution here.

In theory phytoplankton would need to grow/reproduce in your tank to bind more phosphate than you introduced by adding it. And then it needs to be filtered out to actually remove the additionally bound phosphate from the system. Sure some of it will be used for coral growth so you might get away with filtering out a bit less, but you get the idea.

Phytoplankton sellers usually recommend to dose phytoplankton when there will be a lot of light for a few hours and to turn off the skimmer so it won't end up being removed immediately.

If phytoplankton actually can counter the effects of having the skimmer turned off for a few hours probably depends on various factors (e.g. a UV sterilizer might stop phytoplankton reproduction reducing efficiency and the skimmer size will also make a difference).

So if dosing phyto doesn't work for you maybe you should view it as coral food well knowing that it will add nutrients instead of reducing them. For getting rid of phosphate you can use macro algae or adsorbers instead.