Phosphates?

[thelonereefer1]

So I have a biocube 29. It’s been up and running since 2013. Currently it’s just a coral tank for me. One yellow coris wrasse which has been in less than a month. Two pieces of rock with Zoas on them smaller than a dollar bill combined. And one decent size piece of rock with some gsp. I’ve never had a nutrient issue until a few weeks ago. I typically would change 5 gal every 2-3 weeks. About a week or two ago I noticed my phosphates crept up to almost .3 (nitrates stay between 4-6). I’ve done a 5 gal change every 2-3 days for the last week and phosphates have gone down but seem to hover around .21-.24. Any suggestions on lowering them? I’d ideally like to see sub.1. I was hoping I could accomplish this either with a larger water change or multiple changes over a period of time.

 

[Morpheosz]

Interesting, I had a similar-ish experience where my phosphates were very low, to the point where I had to supplement for awhile. I had nothing but coralline algae on the sand. Now my phosphates have at times crept up to 0.3 without discernible reason. I started running some GFO (at BRS calculator recommended dose) and within a day or so it knocked it down to almost nothing. I now have it running on a timer on my Apex for a couple hours a day.

Long story short, if you stick some GFO in a baggie in your filter loop it would probably knock it down pretty quick. YMMV, this is my first experience with GFO, but it seems to be fast acting!

 

[X-37B]

On a 29g I would start with 1 tablespoon of Phosgaurd in a nylon bag. Monitor until its in range. You can use gfo but I prefer Phosgaurd.

Tank pic?

 

[thelonereefer1]

On a 29g I would start with 1 tablespoon of Phosgaurd in a nylon bag. Monitor until its in range. You can use gfo but I prefer Phosgaurd.

Tank pic?

Would you remove once phosphate drops in range or leave indefinitely?

 

[thelonereefer1]

Interesting, I had a similar-ish experience where my phosphates were very low, to the point where I had to supplement for awhile. I had nothing but coralline algae on the sand. Now my phosphates have at times crept up to 0.3 without discernible reason. I started running some GFO (at BRS calculator recommended dose) and within a day or so it knocked it down to almost nothing. I now have it running on a timer on my Apex for a couple hours a day.

Long story short, if you stick some GFO in a baggie in your filter loop it would probably knock it down pretty quick. YMMV, this is my first experience with GFO, but it seems to be fast acting!

I’ve only dealt with gfo once in the past and I believe it was user error. As I plopped in the whole bag and left it for I don’t even remember how long. Phosphates of course bottomed out completely. It sure did remove them though lol

 

[X-37B]

Would you remove once phosphate drops in range or leave indefinitely?

Nice system!
Depends as the only way to tell is to monitor it.
Once it comes down into your desired range test every few days.
Once it starts going up change it out and repeat.

For reference my 45 runs phosgaurd 24/7. My 80g I dose po4. 20g does not require any yet its 3 months old.

So just remember to start using a small amount. You can always add more. Using to much of either can bottom out po4.

1 tablespoon may not lower po4 enough but its best to start low and work up.

Do you run carbon as it helps reduce the organic load?

 

[thelonereefer1]

Thanks! I actually don’t run anything on this particular system. I never have to be honest. I’ve been trying to think of there’s anything I’ve changed recently that could maybe be linked to this. The only thing I’ve done is blow out all the detritus from one of the back chambers before a water change. It wasn’t an enormous amount but it also wasn’t a tiny bit either

 

[thelonereefer1]

Do we think that stirring up years and years of detritus out of the back chambers could cause this increase in phosphates?

 

[Randy Holmes-Farley Verified Community Expert]

. Any suggestions on lowering them? I’d ideally like to see sub.1. I was hoping I could accomplish this either with a larger water change or multiple changes over a period of time.

Water changes generally are not a good way to reduce phosphate because, unlike nitrate, so much binds to rock and sand that it can pop back up nearly to the same level after even a 100% change. Ongoing export is needed to lower it in most cases.

 

[thelonereefer1]

Water changes generally are not a good way to reduce phosphate because, unlike nitrate, so much binds to rock and sand that it can pop back up nearly to the same level after even a 100% change. Ongoing export is needed to lower it in most cases.

As in through the use of a product such as gfo, phosgard, etc? It’s really bugging me to find out what would cause the recent spike. It used to easily stay sub .1 for years

 

[thelonereefer1]

Water changes generally are not a good way to reduce phosphate because, unlike nitrate, so much binds to rock and sand that it can pop back up nearly to the same level after even a 100% change. Ongoing export is needed to lower it in most cases.

As in through the use of a product such as gfo, phosgard, etc? It’s really bugging me to find out what would cause the recent spike. It used to easily stay sub .1 for years

 

[Randy Holmes-Farley Verified Community Expert]

As in through the use of a product such as gfo, phosgard, etc? It’s really bugging me to find out what would cause the recent spike. It used to easily stay sub .1 for years

Yes, or growing macroalgae or other organisms.

 

[thelonereefer1]

Yes, or growing macroalgae or other organisms.

Thank you for the explanation!