Causes of sustained PO4 levels?

Swell · Mar 4, 2020

March 1st, 2020
phos - .432

Followed by a ~60% water change, completely new filter socks, sand siphon, cut feeding back from twice a day to once a day.

March 3
phos - .451

Just to be sure, I measured the phos in my mixing tank, which was 0.018.

What other factors could be causing such a sustained level of phos, especially after such a dramatic water change? What should my next steps be?

Richard Newman · Mar 4, 2020

Hi @Swell,
I'm sure other more experienced folks will weigh in, but I have read that rocks can leach out phosphate. It might take several large water changes before any reduction is seen.

You can always run GFO. I run some due to my heavy handed feedings. For the moment I'm probably averaging .1 phosphate.

Good luck!

Swell · Mar 4, 2020

Thank you! What a pain... I have begun dosing Phosphat-E, as well. I guess I'm going to step up 1.5% water changes to every 4 hours until things come down.

Miller535 · Mar 4, 2020

What are your nitrates at?

Swell · Mar 4, 2020

Miller535 said:
What are your nitrates at?

12-25 based on NYOS

W1ngz · Mar 4, 2020

I guess I'm going to step up 1.5% water changes to every 4 hours until things come down.

Sounds like an automatic water change setup?

Another single much (much) larger manual water change would be more effective to knock a parameter down. Reading a little on how Phosphat-E works, it sounds like to truly remove the phosphate from the system it needs some agressive skimming and/or frequent replacement of socks or filter floss. Personally, I'd go with another large water change and some agressive GFO for a few days to remove the compounds from the system entirely instead of just binding them and waiting for a second step (skimming/mechanical) to export them.

Larry L · Mar 4, 2020

If you really have a bunch of phosphates built up in your rock or sandbed, small daily water changes are not going to be a very effective way to get that out. Repeated big water changes, with enough time in between for the phosphate to leach out of the rock/sand and reach equilibrium with the water, would work better - but that could be kinda disruptive to the tank and could get expensive. I think you're better off dosing the Phosphat-E (or something similar) to knock things down. You might need to do repeated doses until all the surplus phosphate has been depleted.

I wrote a calculator to help with getting the Phosphate-E dosage right: http://larryl.emailplus.org/fish/dosing-instructions-phosphate-removers.html

Swell · Mar 4, 2020

W1ngz said:
Sounds like an automatic water change setup?

Another single much (much) larger manual water change would be more effective to knock a parameter down. Reading a little on how Phosphat-E works, it sounds like to truly remove the phosphate from the system it needs some agressive skimming and/or frequent replacement of socks or filter floss. Personally, I'd go with another large water change and some agressive GFO for a few days to remove the compounds from the system entirely instead of just binding them and waiting for a second step (skimming/mechanical) to export them.

I have a good deal of sticks in there. I'm primarily concerned with cutting the phos down too low and shocking everything, which is why I've adapted frequent, gradual water changes along with mechanical removal. Without considering rock volume, I am getting at least 2% water changes every 4 hours, turning over 12% in a single day.

Alternatively, concerned about the detriment to continued increases in my phos. So is it truly wise to implement such a big change? Or are you implying that even with a big change, the phos will still only be minutely impacted?

Also noted on the Phos-E. I have never run GFO before, so I will begin researching that.

W1ngz · Mar 4, 2020

Swell said:
even with a big change, the phos will still only be minutely impacted

I can only guess at that part since it depends on the source. If for whatever reason it's in the rocks and sand, getting it out of the water is easy but then it will come back to equilibrium with whatever leeches out of the rocks. Then you have to remove it from the water again.

Rinse, repeat.

If you track your phosphate levels, GFO would be less laborious and a more consistently sustained downward pressure on the levels to draw it out of the rocks and since you're tracking it you can see when to stop or shut off the reactor for a day and observe how it behaves.

Nicholas Dushynsky · Mar 4, 2020

If you are doing frequent water changes and the water you are putting in has phosphates in it, it won't lower it will raise it. Why not let the corals use the phosphates to grow and stop changing water, also that in turn won't risk bottoming out po4 and risk killing your corals. Are the corals growing still?

Miller535 · Mar 4, 2020

Swell said:
12-25 based on NYOS

I was originally thinking maybe you nitrate and phosphates were out of balance. But that is not the case. How does everything look in your tank? How do your corals look?

Swell · Mar 4, 2020

Oddly enough my ORA Hawkins is fairing well, but multiple montis and other acros have begun getting ticked. Even my old age slimer started bleaching, which is what caught my attention in the first place. This is a 3 year old tank.

Miller535 · Mar 4, 2020

If it were me, I would try and run some GFO then. Personally I think the recommendations are WAY too high. Maybe only put in 1/4 of the recommended amount and check your po4 the next day.

Miller535 · Mar 4, 2020

By the way, what are you measuring po4 with?

Swell · Mar 4, 2020

Hanna Phos-ULR
Recommendations are too high for what exactly?

paraletho · Mar 4, 2020

Smaller amts of gfo with more frequent media changes are better for SPS. Did this level creep up over time or is this a recent thing. Are you missing any fish?

Miller535 · Mar 4, 2020

Swell said:
Hanna Phos-ULR
Recommendations are too high for what exactly?

For how much GFO to use. IMO. strips it too low too fast.

Swell · Mar 4, 2020

paraletho said:
Smaller amts of gfo with more frequent media changes are better for SPS. Did this level creep up over time or is this a recent thing. Are you missing any fish?

Slow creep. I typically test my phos once a month, but it exponentially rose this past month.