effectiveness of GFO

[neiltus]

Hanna said my 80g was at .44, salifert confirmed close to .5.

Started BRS high density GFO last night (half a cup, their calc said 2/3 of a cup), did a 15g water change today, Hanna came in at .17, salifert was around .25 (color reading/light/eyes).

Assuming Hanna is spot on, a 15g WC would have diluted my 80g to about .36~.

Does GFO work that fast to reduce from .36 to .17 in less than 24 hours?

 

[Sonyardo]

I've seen gfo strip phosphates out of the water very fast. But that was probably too much GFO too fast Good for you for reading the instructions.

 

[neiltus]

I am thinking if I knocked of .2ppm overnight, that might be to much GFO

 

[fcmatt]

I agree. Too much gfo. I have to wonder if it will hurt corals when dropping it that fast.

 

[neiltus]

Going to test again in about 9 hours and see what I get...I guess I could remove some of the media or just turn off and let sit.

Honestly, I have seen some other posts on here about using GFO and have seen it take two or three weeks to get it to come down that low...shocked at my result so far.

 

[Sk8r]

It's tricky. It can saturate fast, does no color change to say it's 'full up', and sit there doing nothing else from then on. When I use it, I change out medium monthly.

 

[jayball]

I would use much less and change it fairly often untill you get it in a better range. 1/8 of a cup (2 tbsp) will cause a smaller shift and can be changed weekly until the PO4 falls into your desired range.

 

[neiltus]

.24 this morning via hanna. I recall someone saying the margin on hanna is +/- .03, so if pushing the edge of the z-values it makes sense to say the .5 cup cut about .16 +/- .03 off of the phosphate in 36 hours. I am going to test it again tomorrow and see where I am at...as Sk8r says, it can go fast, and I could have had the bump early on and it could just edge.

Will test daily and update.

 

[neiltus]

.19 this morning, running the pump wide open and it appears the GFO has fused.

Can I shut the pump down and break up the GFO?

 

[neiltus]

.23 this morning, shut the pump down and stirred the GFO because it was clumping, will see what it tests in the morning. Since it held at ~.19-.24, I am curious if it saturated that quick from the .5 I was testing at prior.

 

[neiltus]

.17 this morning

 

[fcmatt]

Sounds like it seriously stripped phos right away and now it is losing effectiveness rapidly. It may very well be saturated soon if not already.

 

[taby15]

What type of gfo would you recommend for a nano aquarium?

 

[neiltus]

I changed it out on the 19th to rox.8 carbon (.5 cup) and the high density BRS GFO (.25 cup).

I had done a 3 day lights out to clear up some diatoms, after the no light period was over yesterday my PO4 tested at .3, out of curiosity I checked my PO4 of my mixed saltwater using HW Marinemix Reef, and it came in at .04. So I 'concluded'...

-I think a minor amount is creeping in via the salt mix or from my RODI.
-The lights out period could have put more PO4 'in suspension' from the diatom die off. The gha in the tank looks a little more thinner or dying since the treatment. I did not have a lot visible in the tank...

I added a 2nd DI resin container after my DI on my RO, as well as a 2nd carbon block. My solids after the membrane were about 4ppm and after the DI 0ppm both before and after the additional DI resin container.

Did a big water change today, about 25%. Going to test again later tonight and possibly add more GFO.

TABY-to answer your question, I have only used the BRS high density GFO. I do have some of the two little fishes synthetic GFO at the house, I may try that tonight pending the test.

The rest of the tank tested well yesterday (salifert)
Kh-8.48
Ca-450
Mg-1350
NO3-was 25ppm

I think I am still having measurable die off from my rock and this will be an ongoing process.

In other news-My Potter's angel and Yellow Prawn Goby are finishing up their last 2 days of TTM, I have done 6 transfers after the initial formalin dip, I did Prazi a week ago for 24 hours, they are in their 6th tank, with prazi, for the next 48 hours and will go into observation for 4-6 weeks after this last TTM stage. Both are eating well (was worried about the potters) and are showing no sights of stress. Prazi dose was 2ml to 7.5gallons of water.

 

[neiltus]

Welp, after a 17.5 gallon water change, my PO4 was .33 per Hanna. Added the TLF PO4 remover late last night, this afternoon I was at .11

FWIW, I used less TLF than I did with the BRS media. Since people have asked, it's about the same dust wise. I rinsed well and I put a filter sock on the end of the effluent in wishful thinking.

I think GFO works pretty darn fast...however I think with my rock (really not feeding the tank yet) I am going to just have to shell out the coin and let it do it's thing over months.

I am patient.