Is it normal for Phosphate levels to bounce around?

SteveG_inDC · Mar 1, 2021

I'm not sure if these include some bad readings (like the spike on 2/22) or whether this is normal fluctuation for phosphate levels. I'm trying to figure out how often I should test and how aggressively to feed/run phosphate remover.

Note that the x-axis is messed up. It assumes each measurement is the same interval, which it definitely is not. I've raised this with the developer of aquatic log but he hasn't fixed it yet. At least my testing is approximately every other day so this graph isn't too distorted. I have not figured out how to annotate the graph with events like water and equipment changes.

System is 250g
Feeding ~2 cubes/day + 1 sheet nori on average
Ran GFO for a while, then took offline, ran phosguard on a timer ~6 hours/day

mdb_talon · Mar 1, 2021

I think some fluctuation is normal, but other than right at the start it looks reasonably stable considering testing error. The Feb 22 seems the only real outlier in my mind. There is some natural error margin in all tests....then factor in human error(not getting sample qty exact, not getting all regeant, not mixed enough, etc)

Dan_P · Mar 1, 2021

SteveG_inDC said:
I'm not sure if these include some bad readings (like the spike on 2/22) or whether this is normal fluctuation for phosphate levels. I'm trying to figure out how often I should test and how aggressively to feed/run phosphate remover.

Note that the x-axis is messed up. It assumes each measurement is the same interval, which it definitely is not. I've raised this with the developer of aquatic log but he hasn't fixed it yet. At least my testing is approximately every other day so this graph isn't too distorted. I have not figured out how to annotate the graph with events like water and equipment changes.

System is 250g
Feeding ~2 cubes/day + 1 sheet nori on average
Ran GFO for a while, then took offline, ran phosguard on a timer ~6 hours/day

if you are using the Hanna Checker, these numbers are approximately the same.

Pistondog · Mar 1, 2021

Looks good to me.

stanlalee · Mar 1, 2021

Mine like crazy between feeding and the next day. That to me is actually the difference between expert level reefers and us peasants. They have managed to automate or time feeding, amino acids and export to actually maintain something consistent hour to hour, day to day. I can go from 0.0 on the regular (not ultra low) Hanna to 0.12 over a 24 hour period with a feeding somewhere in there. I'd be happy with a 0.03-0.09 range.

Pistondog · Mar 1, 2021

stanlalee said:
Mine like crazy between feeding and the next day. That to me is actually the difference between expert level reefers and us peasants. They have managed to automate or time feeding, amino acids and export to actually maintain something consistent hour to hour, day to day. I can go from 0.0 on the regular (not ultra low) Hanna to 0.12 over a 24 hour period with a feeding somewhere in there. I'd be happy with a 0.03-0.09 range.

Nutrient, ph alk swings in a 24 period are normal, that's why we measure for trends at the same time each day.

stanlalee · Mar 1, 2021

Pistondog said:
Nutrient, ph alk swings in a 24 period are normal, that's why we measure for trends at the same time each day.

I know but there are many people who use those trends and then counter those swings by autodosing (aminos, carbon sources, alk etc) at certain times to minimize those swings. I don't think phosphate levels and "dissolved" nutrients swing much in nature although temps do yet people still try to keep that within 0.5 deg F

mdb_talon · Mar 1, 2021

stanlalee said:
I know but there are many people who use those trends and then counter those swings by autodosing (aminos, carbon sources, alk etc) at certain times to minimize those swings. I don't think phosphate levels and "dissolved" nutrients swing much in nature although temps do yet people still try to keep that within 0.5 deg F

We try to keep the "ideal" scenario as we understand it.....not necessarily to exactly match the ocean. Temperature stability is generally a good thing. Stability of phosphate is ideal also, but at that scale very difficult.