Phosphates rising after changing HC GFO

shellynjason · Mar 17, 2013

So for three weeks I have been running HC GFO in a BRS dual reactor. I went from .41 to .21 in a week, then the GFO was saturated and I changed it out. Then week two it got down to .11 and I could tell phosphates were percipating out of the LV and substrate because it would stay steady all week between .13 and .09.

Friday I for the second time changed out the HC GFO, the phosphates (per Hanna checker ) were .11. Each of my change out I use a bit more then a 1/2 cup for a 120g tank. So Saturday I expected it to be under .11, but instead it was .13. Today I just checked it REALLY expecting it to be lower and it was .16.

1. Why would my phosphates be going UP after changing the high capicity GFO out? (note: tank has been running since oct. 2011, and I have three small fish and a 3" tang) with minimal feeding and nitrates show zero all other params are spot on, my skimmer is pulling yuck out just fine).

2. How long does it take to leach phosphates out of 100lbs of live rock and 3/4 sand bed) ? thought maybe someone might know this

3. How much phosphates can 1/2 of HC GFO absorb? ... ( I seem to get saturated at about .20 - .30 in five days, of course I have no idea of the accuracy because I am not 100% sure of the live rock phosphate percipitation daily)

I would appreciate hearing from everyone else's experience

Otter_rs · Mar 17, 2013

It's not easy to answer all your questions about your phosphate issues, but one very important thing to remember is that your test kit only tests for one form of inorganic phosphates. You may have higher organic phosphate loads that is exhausting your GFO and leaving higher inorganic readings. Your test kit only reads a percentage of available phosphates in your aquarium. I would recommend you keep up with the GFO and be patient. You can also consider using calcium hydroxide drips to help and also bio pellets is an option. Good luck.

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dankreef · Mar 17, 2013

If you don't already, I would syphon your sandbed is probably leaching it out. If you havn't touched it only do a small part of it at a time. Like otter said you could have organic p04 that you can't test for.

shellynjason · Mar 17, 2013

Thanks dankreef and otter_rs! I do weekly 10% water changes and always siphon small areas of the sand bad. I have 100ml Ecobak in a Ehiem for the last three weeks , just because after I 'finally' get the HC GFO to get my phosphates to .04 I plan on running more Ecobak so right now it's just a little to get seeded and until I get a better reactor for the Ecobak.

This was just discouraging because since I started the HC GFO I have seen it go down almost daily, until this change out and now it's like it isn't doing anything. I see the 'slight' tumble so it's not clogged. I don't have cyno or excessive algae just the typical daily film on the sides that I use the magnet to daily.

Otter_rs · Mar 17, 2013

All I can say is just be patient... It will work out if you keep at it.

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shellynjason · Mar 19, 2013

Well yesterday p04 was .13 per Hanna Checker and today it is .15. So it is rising daily since my Friday change out.

My confusion is .... If I am to change my GFO when phosphates start to rise, and do exactly that. But then it continues to rise daily after the change then assumption is I need to change this HC GFO almost daily. This sounds really wrong to me.

Has this happened to anyone else?

Mike&Terry · Mar 19, 2013

We normally test the effluent coming out of the GFO reactor to determine if the media is exhausted.

shellynjason · Mar 19, 2013

Mike&Terry said:
We normally test the effluent coming out of the GFO reactor to determine if the media is exhausted.

Ok just checked the output water from my dual BRS reactor and it reads .09.

I will change it out again. Who knows maybe 1/2 cup of HC GFO gets saturated in one day. Though the first week I went from .41 to .21 over six days.

I found a thread where a guy went from 2.xx to .25 in days with 2 cups of GFO., that is like a .50ppm absorption per 1/2 cup.

J&O'sdad · Mar 19, 2013

If the effluent has a lower reading than the tank water it is working and should not be changed yet. That is the way I figure out to change mine.

shellynjason · Mar 19, 2013

I just went ahead and changed it out , to 3/4 of a cup of HC GFO this time. Tested my ro/di and it is 0.00 and ran through a few gallons of fresh ro/di to clean the dust off before placing in the DT.

Since the Friday GFO changed that didn't seem to do a thing the only other change was a 3" puple tang was added , but my feeding amount did not change because he is to busy chasing his reflection to eat. Could one additional fish cause HC GFO not to keep up? hmmm variables ...

I will check the phosphate levels every few hours to see if I see any noticable drop in phosphates this time. My morning check was .15 so we'll see at my 6:30pm check in *smile* ...

shellynjason · Mar 19, 2013

WOW !!!!!!!!!!!!!!!!!!!! I have my answer ... at 6:30pm two hours after changing out the HC GFO my phosphates read .06 . Therefore the GFO is working and it is just leaching out of the rock and substrate once the media gets saturated. Awesome that makes me feel better at least.

shellynjason · Mar 20, 2013

Note my 10pm check that same night showed my phosphates where now slowly rising again , hanna checker showed .08. Can't wait to see what they are tonight after work ... hmmm.

shellynjason · Mar 22, 2013

My 3/20/2013 10pm check on that same day showed phosphates were right back were I started at .11. I still was there was a better way to check the media itself to tell if it is actually exhausted.

so Thursday I changed out the HC GFO again, another 1/2 cup. I choose not to go with 1 cup because the BRS reactor doesn't seem to move (slow tumble) the media with that much in it). So before the Thurday 4pm change the phosphates in the 120g water column read .11 and then my 8pm check showed them down to .06. I fell like I am in a endless loop :neutral:

Otter_rs · Mar 22, 2013

It's not endless unless you are adding more phosphates than you are taking out. Again, I would not put that much stock in your test readings, it tells you very little about your phosphate concentrations. Battling high phosphates takes time and patients. It won't happen in just a couple weeks. It may take you over a year to get things under control.

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shellynjason · Mar 28, 2013

Otter_rs said:
It's not endless unless you are adding more phosphates than you are taking out. Again, I would not put that much stock in your test readings, it tells you very little about your phosphate concentrations. Battling high phosphates takes time and patients. It won't happen in just a couple weeks. It may take you over a year to get things under control.

Isn't that the truth! I had gotten as low as .06-.07 by doing daily GFO changes, then decided to just leave the GFO for a few days now my readings are back up to .22 last night. So it seems I am in for a long battle if I want to raise sps and keep my nutrients low.

AlbertGF · Nov 21, 2014

Hello,

shellynjason, how did this finish??

I'm having the same problem, my phosphates were at 0.1 (salifert test). I decided to try Ultra Phos, it's not iron based, it's aluminium, but I think it's more or less the same.

The problem is that the day after I introduced this into my tank my readings were 0.5!!!! The phosphates went up instead of down!!!!

Now I don't know if it's normal because of the organic phosphates and phosphates leaching by the LR or there is another problem I can not find.

Thank You.

Regards.

P.D. Sorry for my english, I don't speak that language very well.

Randy Holmes-Farley · Nov 21, 2014

shellynjason said:
Ok just checked the output water from my dual BRS reactor and it reads .09.

I will change it out again. Who knows maybe 1/2 cup of HC GFO gets saturated in one day. Though the first week I went from .41 to .21 over six days.

I found a thread where a guy went from 2.xx to .25 in days with 2 cups of GFO., that is like a .50ppm absorption per 1/2 cup.

The higher phosphate is, the more rapidly the GFO is depleted. 5 days at 0.2 ppm could certainly deplete it if the flow through it is good. Even 24 h may be enough if the flow is adequate to keep bring new phosphate to the GFO.

You can't really state a fixed amount that can be bound and then you are depleted because the amount that binds increases as the free phosphate concentration rises,a nd other things also bind to the same binding sites, such as silicate and organics.

It can take a significant amount of both time and binder to deplete what is bound to the surface of live rock after the rock is exposed to elevated phosphate. The rock is essentially acting like more GFO.

FreeEnergyReefer · Jan 21, 2021

I know this threads old but I am experiencing similar issues atm. Its a 125g total volume mixed reef. Tanks been running for a year phosphates always stayed around .03-.05. So I never had to run gfo. I started dosing that red sea ab+ 45days ago. Dosed it every other day for a month then stopped because GHA & Bryopsis were popping up everywhere. I test my nitrates n phosphates, nitrates -10, phosphates -.14. So I scrub all the algae off the rocks, vacuum the sanded n do a larger than normal water change. After a week I repeat the process and add GFO. Now the algae is all but gone but my phosphates are .17. How is it possible that after adding a phosphate removal media my phosphates went up? Just doesn't make sense. I need to get my phosphates back in check so this algae doesn't make a comeback.

Randy Holmes-Farley · Jan 21, 2021

FreeEnergyReefer said:
So I scrub all the algae off the rocks, vacuum the sanded n do a larger than normal water change. After a week I repeat the process and add GFO. Now the algae is all but gone but my phosphates are .17. How is it possible that after adding a phosphate removal media my phosphates went up? Just doesn't make sense. I need to get my phosphates back in check so this algae doesn't make a comeback.

If you removed algae, you removed one of the sinks for phosphate and it may rise for that reason.

FreeEnergyReefer · Jan 24, 2021

Randy Holmes-Farley said:
If you removed algae, you removed one of the sinks for phosphate and it may rise for that reason.

Thought if I removed the algae that the phosphates went with it. Guess what u mean in a nutshell is the phosphates have less surface area to bond too. Just added more gfo we'll see what happens. I dont wanna strip my water to zero phosphates