Phosphate Control

[Dr RBG]

My phosphate level (with Hanna UL checker is running in the 0.1 level. I would like to drop it to below this as recommended. I have been feeding less in general (mysis in the PM and pellets in the AM) and have about 8 fish, none bigger than about 2 inches in a 100 gallon with about 20 gal sump.

What would you suggest I should do to try to lower it? Bio-pellets G.F.O. or something else.

Thanks

 

[Firemanreefkeeper]

I use high compacity GFO in a reactor and get mine down to .075 while still feeding heavy. I change it out about every 6 weeks when it starts creeping up. .1 isn't bad, that's only like 34ppb using the Hanna convention chart.

 

[jda]

.1 is not bad, but if you want to lower it, then GFO will work better than organic carbon.

First, you have to understand that the phosphate that you want to remove is bound up in the sand and rock (aragonite) in your tank. As you lower the concentration in the water column, the aragonite will release more. If you use too much GFO, then your water column level can bounce really low and then bounce back up when the aragonite releases.

The key is to use very little GFO and change it often. You want the decline to be slow, steady and without any downward or upward spikes. Lowering phosphates is not an issue - lowering them too fast certainly is.

I would do something like using a couple of tablespoons in a reactor, put very slow flow through it and then change it ever few days. When the water coming out of the reactor has the same level as the tank (or near), then it is exhausted and you can use this as a guide. What you want is to test like 34 ppb one week, 33 the next, 32 the next, etc. You do not want 34 to start, then 12 (using too much GFO), then 33 (aragonite releases), then 10 (too much GFO), then 32, etc... this is where stuff starts to get mad.

 

[RCS82]

Jda pretty much nailed it.
But how old is your tank? 0.1 isn't that bad at all. A few good weekly water changes might be all you need. I can't see anything suffering though if your PO4 is a steady 0.1

 

[Dr RBG]

Thanks. I dont think there is room for a reactor. could I just put it in a bag in the sump?

 

[Mastiffsrule]

Just a question, you mentioned fish, any coral? If not as mentioned that level is fine. I also agree w JDA on lowering slow,

But I just did the opposite. My reef does not,have any sps so I put a cup high cap gfo in a reactor and dropped from above 1 to .03 in 8 days. I am not abdicating that, just mentioning it. I think what is in the tank may factor in as well.

 

[Dr RBG]

I do have mostly soft corals like mushrooms and hammer corals

 

[Firemanreefkeeper]

You can put it into a media bag, it won't be as efficient but it will work. My friend uses chemipure (I think it's chemipure) in a bag in his sump and he swears by it

 

[Hemmdog]

You can put it into a media bag, it won't be as efficient but it will work. My friend uses chemipure (I think it's chemipure) in a bag in his sump and he swears by it

I use a small chemipure elite(gfo) rated for 25 gals in my 90. It’s doing good at slowly lowering phosphates. Already in a media bag, also has some resin beads in it to help with water clarity as a bonus. I’ve had good luck with elite for phosphates and blue if nitrates are creeping up. I mainly just don’t want to deal with a mess of making my own media bag, I used to do that..

 

[Billldg]

I have a 120 gal tank with a 30 gal sump, so close to your setup, after my tank rebuild I purposely let the nitrates and phosphates get higher to encourage algae growth to combat what was left of the dinos. Now that I have some green algae growing and my dinos r finally starting to go away I started to lower my phosphates. My parameters were at 20 nitrate/red sea, and .17 phosphates/hanna. I often use the calculator at BRS for dosing and such, I always use 1 cup of carbon, but it also recommends using 1 cup of GFO, having used this stuf in the past I know that if you use that much your phosphates will plummet to 0 ppm. So for the past month I used 1 cup of carbon and a 1/4 cup of GFO mixed together and my phosphates slowly went down to .1, I have only checked phosphates once sense the last time I changed GFO last weekend and it was at .1 also, I expect it to still drop slowly, but that's what you want, I feed a little heavily to keep my tangs from going to war with each other. I use a carbon reactor with a small pump in my sump and just mix in a little GFO, mixing the carbon and GFO keeps the GFO from turning into a brick if not tumbled lightly.

 

[jda]

GFO that is not used quickly will get coated in organics and stop binding phosphate. Media in a bag can get like this quickly. This is another reason why a small amount, changed often, is the best way to go.