GFO Confusion

ArmyReefer · May 31, 2019

Okay quickly about my tank. 3 weeks ago upgraded from an old red sea max 250 to a RSR 450. I hard plumbed in two reactors, one for GFO and the other for bio pellets. Put in a small refugium made out of egg crate with Chaeto, correctly sized skimmer.

I immediately put online the bio pellets and after a week put in Rowa Phos to the other reactor. here is what my system has been out.

Salinity 1.026
NO3 5 (Red Sea) just got a nyos because I honestly cant tell when they get low
PO4 .03 (hanna)
ALK 8.6 (hanna)
Calcium 450 (Red Sea)
Magnesium 1360 (red Sea)

All has been smooth sailing then all of a sudden my PO4 jumped to .104. The Rowa 85g has been in the reactor for a week so I would not think it is depleted yet but could be wrong. I have a pretty high bio load but do not feed a ton. 3 sheets of NORI and 2 cubes a day.

So the questions.
What would have made my phosphate jump so quickly?
notes:
1. Filter socks were clogged and over flowing after three days and I did not change them out till I caught that.
2. I have an injured large leopard wrasse that disappeared right before the spike, which I found last night dead. Assuming he has been dead for three days.

How do I really know if its time to change out the GFO?

SeaDweller · May 31, 2019

I’d venture a guess and say it was the decaying leopard. I’d double check the test again, and if it’s been 2-3 weeks already, I’d change the rowaphos. Maybe use 45-60 grams instead of the 85g (assuming that’s the “full” amount your tank needs). I use 125 g on my 240 and I am heavily stocked and feed a lot and I keeps my PO between 0.03-0.10.

Personally I wouldn’t worry about the .07 increase, as 0.104 is still pretty low. I gauge my GFO/Rowaphos change schedule depending on how frequently I have to clean the tank panels.

ArmyReefer · May 31, 2019

TitanCi said:
I’d venture a guess and say it was the decaying leopard. I’d double check the test again, and if it’s been 2-3 weeks already, I’d change the rowaphos. Maybe use 45-60 grams instead of the 85g (assuming that’s the “full” amount your tank needs). I use 125 g on my 240 and I am heavily stocked and feed a lot and I keeps my PO between 0.03-0.10.

Personally I wouldn’t worry about the .07 increase, as 0.104 is still pretty low. I gauge my GFO/Rowaphos change schedule depending on how frequently I have to clean the tank panels.

Thanks, not overly concerned although I would prefer to stay between .03-.07. Was more concerned at the jump in it.

ArmyReefer · May 31, 2019

TitanCi said:
I’d venture a guess and say it was the decaying leopard. I’d double check the test again, and if it’s been 2-3 weeks already, I’d change the rowaphos. Maybe use 45-60 grams instead of the 85g (assuming that’s the “full” amount your tank needs). I use 125 g on my 240 and I am heavily stocked and feed a lot and I keeps my PO between 0.03-0.10.

Personally I wouldn’t worry about the .07 increase, as 0.104 is still pretty low. I gauge my GFO/Rowaphos change schedule depending on how frequently I have to clean the tank panels.

Titan.

How often would you say you change it?

SeaDweller · May 31, 2019

ArmyReefer said:
Titan.

How often would you say you change it?

I’m on like a 2-3 week schedule, I don’t stress it too much. If I see film algae getting out of hand then I’ll change it. I only use half of what Rowaphos recommends.

The trap is when people try to chase “ideal” numbers. The mantra of “knowing your tank” and “stop chasing numbers” is true. You have to see your inhabitants and get a feel of when they’re happy or not.

Say your PO4 is 0.10 and all is healthy and fine, do you need to change that value? Probably not. And if you DO then maybe change it a bit at a time. Now if your PO4 is creeping up to say 0.25 or whatever and things look like crap, then yeah implement some change, but take it slow.

DangerDave · May 31, 2019

The filter socks could be adding to it. I have been running sockless since my vacation in April. I’ve been struggling with low nutrients since my return. I added socks back to lessen the detritus that’s been accumulating in my bare bottom frag tank (everything is plumbed together). Since adding the socks back, I’ve found it easier to keep my nutrients up. I think it’s sitting in there for days and breaking down, instead of getting pulled out by the skimmer. Kind of counterintuitive, but it’s working....

Dan_P · May 31, 2019

ArmyReefer said:
Okay quickly about my tank. 3 weeks ago upgraded from an old red sea max 250 to a RSR 450. I hard plumbed in two reactors, one for GFO and the other for bio pellets. Put in a small refugium made out of egg crate with Chaeto, correctly sized skimmer.

I immediately put online the bio pellets and after a week put in Rowa Phos to the other reactor. here is what my system has been out.

Salinity 1.026
NO3 5 (Red Sea) just got a nyos because I honestly cant tell when they get low
PO4 .03 (hanna)
ALK 8.6 (hanna)
Calcium 450 (Red Sea)
Magnesium 1360 (red Sea)

All has been smooth sailing then all of a sudden my PO4 jumped to .104. The Rowa 85g has been in the reactor for a week so I would not think it is depleted yet but could be wrong. I have a pretty high bio load but do not feed a ton. 3 sheets of NORI and 2 cubes a day.

So the questions.
What would have made my phosphate jump so quickly?
notes:
1. Filter socks were clogged and over flowing after three days and I did not change them out till I caught that.
2. I have an injured large leopard wrasse that disappeared right before the spike, which I found last night dead. Assuming he has been dead for three days.

How do I really know if its time to change out the GFO?

A few ideas for your consideration.

Some GFO users measure the PO4 level at the output of the reactor. The output should be lower than the level going in. When it is not, change the GFO.

Removing PO4 with GFO may starve your Chaeto and the bacteria trying to grow on the bio pellets.

The nitrate level in the system isn’t all that high. Chaeto or bio pellets should be enough when not PO4 starved.

Your system is very new. Fluctuations in nutrient levels should be expected. Not sure how often you take measurements. Maybe the PO4 level did not “suddenly” change but gradually climbed.