Can GFO work too well?

[Bill_Moorman]

Morning all!

I recently added a BRS mini reactor to run carbon and GFO. I was reading .53 phosphates on Monday before adding the reactor, over night it dropped to .14, 24 hours later I was at .12, and this morning I read .00 on my Hanna checker.

I know having some phosphates is okay, so wonder if having .00 phosphates and under 1.0 nitrates is okay (tested yesterday with NYOS). The nitrate test color was lighter than the 1.0 on the color scale, but not 100% clear, so I’m in the 0-1 range.

About my tank:

40b set up since January, only inhabitants are two clowns, moderately stocked with LPS and a few SPS. Running an AquaC Urchin skimmer. Currently seeing growth of GHA, not in plague proportions but it’s there.

I have a 10g sump with a volleyball sized chunk of chaeto, which grew from a softball size.

Params:

Phosphate 0- Hanna LR phosphate
Nitrate: <1- NYOS
Alk: 8.7-Hanna
Calc: 450- Red Sea
Mag: 1440- Red Sea
Salinity- 35- calibrated refractometer
pH: Swings between 8.15-8.27-Apex
Temp: Swings between 77.1-79 daily -Apex
Dosing two part via auto BRS doser
Haven’t tested Ammonia or Nitrite in months

I am not sure if I should continue running the reactor, or take it offline until I get a reading above .10 of phosphate and allow it to take it back down.

Thanks in advance!

 

[Breadman03]

It can certainly strip the water column excessively. Testing will help you determine how much to use and how often to use it.

 

[Jason mack]

Agreed .. you need too find the amount that will work for your tank .. so I would suggest using half next time , and then slowly increase the amount everytime you change it

 

[ihavecrabs]

While it is hard to grasp a correct reading for PO4 when there is algae growth, I would be worried about bottoming out PO4 as it has led to cyano and dino blooms in newer systems.

 

[Bill_Moorman]

Would you all suggest that I cut the reactor off for a few days to get some measurable phosphate and then half the amount as said above?

 

[Jason mack]

Would you all suggest that I cut the reactor off for a few days to get some measurable phosphate and then half the amount as said above?

Yes that’s what I would do...

 

[ihavecrabs]

I'd lower the flow through the reactor or if you have some very sensitive SPS, it may be worth taking it offline or at least removing some of the media.

At least until you get a reading on the hanna phosphorus checker.

#reefsquad any additional thoughts?

 

[Bill_Moorman]

Best thing about the Apex...turned it off while at work.

 

[DancingShark]

I have put my gfo on a timer. It runs 4 hours a day. I am trying to find the balance.

 

[ihavecrabs]

If you do turn it off or only run it for a few hours a day, it would be best to run it a few min an hour vs all at once to prevent the water from becoming stagnant.

 

[Reef Dude]

In years past, I found gfo in a reactor to be super aggressive (too much so in my opinion) at removing Phosphates. Many of the coral problems I’ve had in my tanks have been from stripping too much PO4 out of the water. For last few years, I put gfo in a bag inside my sump as needed and have found that this method is passive enough that it will not bottom out my PO4. In my experience, putting less gfo in the reactor will only exhaust the media faster, but it will still bottom out my PO4. Perhaps slowing the flow rate once you get thing back on track could help. I agree with the above in that you should probably keep a little water moving through the reactor rather than keeping is shut off entirely, as the water could become stagnant in there with no flow.

 

[saltwaterpicaso]

how large is your tank I always used to use it and my corals would always fade I always thought I had my lights to bright. combined with a large skimmer I never even needed it to begin with have not used it in years

 

[Bill_Moorman]

Just thinking out loud here...my main goal was to get the phosphates down to slow GHA. I have achieved that. Now I should be able to maintain low levels with WCs and being mindful of feeding.

New plan, remove GFO, and use the reactor for my carbon. Monitor phosphates and use WCs as my primary control method.

Solid enough plan? My whole rationale is that all of my LPS are thriving and I don’t want to risk losing anything due to the GFO.

 

[408Dartfish]

Best thing about the Apex...turned it off while at work.

That’s cool I’m jealous. I’ll get there some day

 

[Potatohead]

In years past, I found gfo in a reactor to be super aggressive (too much so in my opinion) at removing Phosphates. Many of the coral problems I’ve had in my tanks have been from stripping too much PO4 out of the water. For last few years, I put gfo in a bag inside my sump as needed and have found that this method is passive enough that it will not bottom out my PO4. In my experience, putting less gfo in the reactor will only exhaust the media faster, but it will still bottom out my PO4. Perhaps slowing the flow rate once you get thing back on track could help. I agree with the above in that you should probably keep a little water moving through the reactor rather than keeping is shut off entirely, as the water could become stagnant in there with no flow.

I have found the same. Much more success with it in a bag.

I also find as someone said above that really low PO4 with some nitrate and dissolved organics almost always spells cyano.

 

[chipmunkofdoom2]

I have put my gfo on a timer. It runs 4 hours a day. I am trying to find the balance.

It's best to use less GFO as opposed to running it on a timer. The first issue with running GFO on a timer is the water can become stagnant from sitting without moving in an anoxic environment. The second is that GFO will clump together if it is not kept moving. The reason we fluidize GFO in a reactor is because of its tendency to stick together. If the GFO sits for 5/6ths of the day, it will likely clump up and become useless.

 

[Reef Dude]

Just thinking out loud here...my main goal was to get the phosphates down to slow GHA. I have achieved that. Now I should be able to maintain low levels with WCs and being mindful of feeding.

New plan, remove GFO, and use the reactor for my carbon. Monitor phosphates and use WCs as my primary control method.

Solid enough plan? My whole rationale is that all of my LPS are thriving and I don’t want to risk losing anything due to the GFO.

Sounds like a fine plan. Use gfo on an “as needed” basis going forward rather than a 24/7 everyday thing.

 

[JMetaxas]

I use half the recommended quantity of GFO. It seems to keep the #'s at the proper level without getting to zero.

Also, I mix it with my Carbon at a 3:1 ratio. (carbon to GFO)

 

[Randy Holmes-Farley]

I agree with using less GFO rather than a timer, because the water in the tubing and reactor can stagnate when not flowing.

I've mixed GFO and GAC (ROX 0.8), but in that case, you don't likely want it tumbling as the GAC may pulverize.

 

[Bill_Moorman]

Changed out the media over my lunch. Just running Rox 8.0. I will let it run for a few days and recheck phosphate.

I’ll report my findings!