PDA

View Full Version : How much GFO?


duncangweller
01-31-2015, 02:37 AM
Hi all,

I have been doing a lot of reading about GFO recently and I have been struggling to find a rule as far as how much to use.

I have been having algae issues of late and seem to have a constant brown film on my sand bed which is driving me nuts.

I have been running carbon and GFO in a BRS dual reactor for a couple of years and have always followed the BRS calculator, but it seems like it asks for a lot of both for a 90g tank.

Some sites have mentioned that the amounts that BRS recommends are way off base, so I'm curious as to what rules you follow.

How much do you use per gallon (or whatever measurement you use)?

I have also been vodka/vinegar dosing but nothing seems to be happening to my levels, and in the last few days a couple of my corals have started looking a bit pale. Others still look great.

jason604
01-31-2015, 03:30 AM
Go for about 1/2-1" in the canister of Gfo. I put too much my first time using it my tank crashed.

Slyguy00
01-31-2015, 04:05 AM
I would agree with Jason. Start off slow and just work your way up. I bleached my sps the first time I added Rowa. 1 1/2 - 2" should be ok to start with. Just start slow and monitor your phosphates.

duncangweller
01-31-2015, 04:09 AM
It's finny you both say that as I went with the BRS calculator for the last two years and ive been using almost two cups of the stuff.

Slyguy00
01-31-2015, 04:11 AM
holy! lol thats alot. I never trust that BRS calculator. When i first started using it I always did half of what it recommended. Now that I know what my tank consumes, I dont even use it anymore.

jason604
01-31-2015, 05:36 AM
What? 2 cups for a 90g?!! That's massive. Mybe they want u to crash so u can buy a whole new system from them lol

gregzz4
01-31-2015, 06:07 AM
The BRS calculator states I should use .86 cups for my system.
That's about 225mls.
I've been battling algae for over a year and decided to back off my GFO amount.
I'm down to 100mls/month and the algae is under control.
I feel the added Iron from the GFO was part of my issue, not the GFO stripping the system as I've always had some measurable PO4.

lastlight
01-31-2015, 06:46 AM
The calculator told me 1 cup and I thought oh good that's how much I use. They suggest replacement every 4-8 weeks and I've been doing it weekly lol. Might have to test after a week is up to see if this is justified.

Reef Pilot
01-31-2015, 01:49 PM
I don't go by any calculator, just what fits nicely into my refillable canister cartridge which is about 250 ml.This is for a 230g system. I use HC GFO. It last about 2 months for me.

I try to keep my P04 between 0 and 0.04 (Hanna). After a change my P04 goes to zero. I check every 2 weeks or so. When it climbs to 0.04, I stir it up in the canister and it then returns to zero. I usually do this 2 times with the same batch. If it doesn't return to zero, then I know it is time to change.

This routine has been very consistent for me. And keeps my GFO costs down. And my P04 doesn't get out of hand. I find best SPS color and growth at these low levels of P04.

Last year I had some tank troubles and my P04 jumped up to as high as 0.10, and had to increase my GFO changes to get it back down again. My SPS lost color, and growth really slowed. I should mention that some SPS are affected more than others. Some didn't seem to be affected at all. But no question, overall and in general, all SPS does better with low P04.

mikellini
01-31-2015, 02:59 PM
The BRS calculator states I should use .86 cups for my system.
That's about 225mls.
I've been battling algae for over a year and decided to back off my GFO amount.
I'm down to 100mls/month and the algae is under control.
I feel the added Iron from the GFO was part of my issue, not the GFO stripping the system as I've always had some measurable PO4.

Have you thought about using phosguard instead? Or alternating between the two? I know there has been some concern about elevated aluminum levels, but now we've seen Triton tests that show elevated levels of aluminum in some salt mixes (with no obvious ill effects) and other tanks running aluminum phosphate remover with normal levels of aluminum in the water column.

Basically I'm just giving myself a pep talk here because I'm going to use up some Seagel I have laying around (mix of phosguard and matrix carbon). ;)

duncangweller
01-31-2015, 03:24 PM
Wowee, thanks for all the advice.

Whilst I've got your attention....the BRS calculator also says to use 0.84 cups of carbon. Is this also way off base?

Thank again guys... Such a useful bunch

Dunc

jason604
01-31-2015, 03:55 PM
Wowee, thanks for all the advice.

Whilst I've got your attention....the BRS calculator also says to use 0.84 cups of carbon. Is this also way off base?

Thank again guys... Such a useful bunch

Dunc

Sounds about right.

jason604
01-31-2015, 04:00 PM
Here's a pic of how many of my sps died(so did a bit of me) from using too much Gfo too fast. I now bleached and acid bath it and use It as extra filtration in my sump( very very VERY EXPENSIVE filtration)

http://i1292.photobucket.com/albums/b578/kosin604/A36A1F9D-42FE-44F8-9783-4ACE46E09D92_zpshayec15u.jpg (http://s1292.photobucket.com/user/kosin604/media/A36A1F9D-42FE-44F8-9783-4ACE46E09D92_zpshayec15u.jpg.html)

Myka
01-31-2015, 04:55 PM
1 tbsp per 30-50 gallons is a reasonable place to start. I've used this amount in a dozen different tanks.

asylumdown
01-31-2015, 08:49 PM
wouldn't the amount you need and the frequency with which you replace it depend entirely on the amount of phosphate present in your system? I don't think there's a hard and fast rule for x amount per x gallons. If you add a small amount and you have lots of phosphate, your GFO will be exhausted within a matter of days (hours?), and will just be a bunch of rust tumbling in your reactor until you replace it, leading to very little visible difference in your corals or algae growth rates.

If you have almost no phosphate and you add lots of GFO, I doubt anything will happen in your tank, as the levels won't really change all that much. It will just take longer for the GFO to be exhausted.

I think people get in to trouble when they have high phosphate and add lots of GFO, in which case there's a massive, sudden drop. Whether or not this is true for you can be pretty easily determined by testing.

Myka
01-31-2015, 09:36 PM
Asylumdown, I offered an amount that I've found safe to use in a variety of conditions. The trouble is that an aquarium can have a "zero" or near zero reading and still have a lot of phosphate within the aquarium depending which test kit a person is using. Using too much GFO can have major consequences.

asylumdown
01-31-2015, 09:42 PM
Using too much GFO can have major consequences.

Has anyone ever figured out why? I know lots of people have reported problems, but other than a sudden drop in PO4 levels, what else could GFO be doing? I've always been suspicious of GFO in general and think it can cause a few of the problems it's often employed to treat, but do you think that too much GFO is harming corals because of something it's adding to the water, or something it's removing?

reefwars
01-31-2015, 09:45 PM
i change out small amounts more often as oppsosed to larger amounts less often , as per what RHF recommends and has always worked great for me :)

i dont measure or weigh it out but i run maybe 1-2" in a tlf 150 reactor

i change mine out maybe every 2-4 weeks , i dont change it out so much based on the P04 test numbers but i can visually tell when my gfo is exhausted:)

jason604
01-31-2015, 09:52 PM
Has anyone ever figured out why? I know lots of people have reported problems, but other than a sudden drop in PO4 levels, what else could GFO be doing? I've always been suspicious of GFO in general and think it can cause a few of the problems it's often employed to treat, but do you think that too much GFO is harming corals because of something it's adding to the water, or something it's removing?

I suspect that large amt pulls po4 too fast n the tank gets a big shock

reefwars
01-31-2015, 10:13 PM
I suspect that large amt pulls po4 too fast n the tank gets a big shock

be it small or large they would both pull out P04 based on the amount of water ran through them and how much they can pull depends on whats passed through and whats available.

for example a guy who fills a reactor and only runs it for 5 mins a day will most likely pull less phosphates than a guy who runs a much smaller amount and changes it every 24hrs;)

reason being is the amount of water passed through :)

Myka
01-31-2015, 11:41 PM
for example a guy who fills a reactor and only runs it for 5 mins a day will most likely pull less phosphates than a guy who runs a much smaller amount and changes it every 24hrs;)

:lol: