Another GFO/Carbon Reactor to Lower Phosphates Question

[popalud]

I'm looking for some guidance in reducing my PO4 with GFO in my slowly expanding 55g mixed reef. For about the past 2 months, I've leveled out at about .29-.36 (Hanna ULR), with limited feeding, water changes, and chaeto. I'd like to get PO4 down to around .10/.15. I don't have much nuisance algae which I'm attributing to my CUC/lighting schedule, but I'm wanting to get to the targets for the corals I have based on the aquarium I got them from.

I understand there are wide ranges that corals will acclimate to, but I'm trying to lower my range. I just purchased a Little Reactor from TLF, and am planning on the BRS method of 2:1 Carbon/GFO (ROWA Phos). I have a calculated volume of 48g of water in my entire system after displacement. Can anyone please help me dial in a good amount of ROWA Phos? BRS Calc (based on generic GFO) is 0.48 cups, but considering I'm not too bad, I can take it slow, so I would start with 1/4cup ROWA Phos, mixed with 1/2cup Carbon (rox.08).

Nitrates: 5-10, Alk: 8.2-8.5, CA: 400-410, Mg: 1275-1300, pH 7.8 if these help.
Let me know if this is a good start. Thanks!

 

[Shazreef]

I would start with 1/4 cup first and wait about 3 to 4 days while testing each day to see the result, then add more or change out the GFO if required.

It's good to take it slow as you don't want to suddenly drop the phosphate concentration and get your corals shy.

 

[Randy Holmes-Farley Verified Community Expert]

I agree: go very slow. You are barely above my target range anyway (0.06 to 0.3 ppm, and higher may be fine).

 

[popalud]

I agree: go very slow. You are barely above my target range anyway (0.06 to 0.3 ppm, and higher may be fine).

Thanks Randy!

 

[winxp_man]

from what I see in the title, my recommendation is run the Gfo reactor on its own, and the carbon on its own.


My 300g system input 250ml Rowa in a BRS single reactor, dropped from .25 to .16 in two days. Then it slowed down a bit, and stabilized at .08-.10 but I never changed the media. Total water amount in my system is 290g after rock and sand is taken in account. Total before rock and sand is 340g.

 

[DmitryB]

I agree: go very slow. You are barely above my target range anyway (0.06 to 0.3 ppm, and higher may be fine).

Randy takes a lot of stress out of chasing the numbers! I love that. I've stopped freaking out about Phosphates and Nitrates. Even Alkalinity. And mild pH swings.

 

[popalud]

from what I see in the title, my recommendation is run the Gfo reactor on its own, and the carbon on its own.


My 300g system input 250ml Rowa in a BRS single reactor, dropped from .25 to .16 in two days. Then it slowed down a bit, and stabilized at .08-.10 but I never changed the media. Total water amount in my system is 290g after rock and sand is taken in account. Total before rock and sand is 340g.

So I ran half the BRS recommended dose (I used 1/4c ROWA) and saw no improvement (with slight increase to 0.45) with nearly daily testing as I try to dial in my parameters. My last water change I increased to 1/2C ROWA, and 2 days later PO4 tested at 0.18. Understanding this may not be a healthy decrease, I elected to run my reactor 12hrs on/off and see that my PO4 is at .21. Given I cant really adjust the flow in my TLF reactor, I cant think of another way to manage PO4. Any glaring issues with this method? If this is a safe practice, is there logic to running the GFO during the day/off at night or vice versa? Typically I feed at night if that matters.

 

[winxp_man]

So I ran half the BRS recommended dose (I used 1/4c ROWA) and saw no improvement (with slight increase to 0.45) with nearly daily testing as I try to dial in my parameters. My last water change I increased to 1/2C ROWA, and 2 days later PO4 tested at 0.18. Understanding this may not be a healthy decrease, I elected to run my reactor 12hrs on/off and see that my PO4 is at .21. Given I cant really adjust the flow in my TLF reactor, I cant think of another way to manage PO4. Any glaring issues with this method? If this is a safe practice, is there logic to running the GFO during the day/off at night or vice versa? Typically I feed at night if that matters.

When run a Gfo reactor, I run it 24/7. And the flow is enought to give the Gfo a good tumble but not fly around like crazy.

Here is a nice link. Super close to what I did with mine. It’s showing 240 ml of Rowa for my system. And unused 250ml.

rowaphos-calculator.com

 

[Randy Holmes-Farley Verified Community Expert]

Running any reactor part time risks the water becoming stagnant and maybe producing hydrogen sulfide (toxic). If you go the part time route, maybe smell the effluent in restart. You could also get a timer that runs it for multiple on/off cycles per day to reduce the time it sits enclosed in tubing and such.

 

[LeftyReefer]

I elected to run my reactor 12hrs on/off and see that my PO4 is at .21. Given I cant really adjust the flow in my TLF reactor, I cant think of another way to manage PO4. Any glaring issues with this method? If this is a safe practice, is there logic to running the GFO during the day/off at night or vice versa? Typically I feed at night if that matters.

Just add an inexpensive ball valve onto the reactor's input line. Then you will be able to to dial up/down the flow as needed.

I use a variable speed DC pump on my reactor, but even on the lowest pump speed, it still pushes too much water through the reactor at times.

You can also run more GFO this way without worry about bottoming out your phosphates.... if your phosphates start getting too low (bottoming out) just reduce flow through the reactor.

I added a ball valve and can now dial the flow exactly as needed regardless of the media in the reactor.
I run my GFO reactor 24/7. and just dial up/down the flow as needed.

 

[BryanM]

So I ran half the BRS recommended dose (I used 1/4c ROWA) and saw no improvement (with slight increase to 0.45) with nearly daily testing as I try to dial in my parameters. My last water change I increased to 1/2C ROWA, and 2 days later PO4 tested at 0.18. Understanding this may not be a healthy decrease, I elected to run my reactor 12hrs on/off and see that my PO4 is at .21. Given I cant really adjust the flow in my TLF reactor, I cant think of another way to manage PO4. Any glaring issues with this method? If this is a safe practice, is there logic to running the GFO during the day/off at night or vice versa? Typically I feed at night if that matters.

I would just go back to the 1/4 cup and run it 24x7 personally.