GFO amount?

[RealReef7]

Hi how much gfo should I run for the first time? The tank is a 120g display with a 20g sump. The tank is mainly sps/lps and its been running since 2008. I will be running a phosban 150 reactor. Also how do I know if there is too much "tumble" in the reactor?

[firemountain]

I decided to run GFO when my phospates creeped up to .08 ppm and I was cleaning my glass every few days. What are your phosphate readings? SPS do not like sudden and big changes, so make sure you drop your numbers slowly. I ran the regular BRS GFO. For calculation purposes, I used the BRS calculator and cut the recommendation in half. I saw a nice and slow steady drop over a months time and my SPS were not affected.

I am currently at like .04 ppm and will take the GFO offline in the next week or so. You only want it to slightly tumble so it doesn't solidify and become rock solid. Best description would be to consider it a slow rolling boil, and not an eruption like Mt. Vesuvius. Check out a few YouTube videos, that may help with a good visual.

[RealReef7]

I am at 1.5ppm, my corals all look fine except for my smooth skin acros have not completely browned out but they do not look the same, growth and PE has been good on all corals. I dont have any unwanted algae except the glass does get dirty quite often. Just a little background of the tank: I'm running 3 koralia 4's, 2 wp 40's and 1 wp 25 so my tank has plenty of flow for a 4x2x2 tank. For lighting im running an 8 bulb t5 tek fixture. Checked my RO unit again this morning and it reads 0. I feed NLS pellets 1-2 a day or NLS pellets once a day and nori. So not really sure where my phosphates are coming from?

salinity: 1.026
cal: 420
alk: 8.5
nitrates:0
ph: 8.0-8.2

[bertoni]

I might try ¼ cup and see what that does to the phosphate level. That's a small dose, but you can double it if the change is small enough.

I suspect some of the phosphate is coming from the food, and some likely will leach from the rock. If GFO starts to get expensive, you might need to look into alternate approaches, like lanthanum chloride, or consider regenerating the GFO.

[RealReef7]

Well I plan to run gfo until my phosphates is around .03-.05 than just slowly cut down the amount of gfo I run. Thanks for the help. I also plan to do a small dose of brightwell's reef biofuel.

[bertoni]

You're welcome! That sounds like a good plan to me.

[firemountain]

For a point of reference, I ran 1/4 cup of the regular BRS GFO for the past month, and I went from .09 to .03 in that time frame.

[RealReef7]

I was thinking 1/2 or 3/4 cup to start?

[Dan_P]

Hi how much gfo should I run for the first time? The tank is a 120g display with a 20g sump. The tank is mainly sps/lps and its been running since 2008. I will be running a phosban 150 reactor. Also how do I know if there is too much "tumble" in the reactor?

Assuming 140 gallons containing 1.5 ppm phopsphate, the water's total phosphate amount is 777 mg. GFO capacity can be as high as 25 mg phosphate adsorbed per gram of GFO, but probably will be less. This means you will need at least 31 grams. Your plan to use 1/4 cup or so sounds good except it might drop the phosphate faster than your coral would like. You could take longer to bring down your phosphate level by using a smaller amount of GFO, changing it out in a few days if the coral are not reacting badly to the lower phosphate level. GFO adsorbs other things too, so, it might not be just the sudden loss of phophate that annoys the coral.

[firemountain]

I was thinking 1/2 or 3/4 cup to start?

Your tank is double the water volume of mine....and I ran 1/4 cup. Since its your first time, I would still play it safe and try 1/4 cup, esp if you have SPS. The last thing you want to do is stress them out.

If your weekly readings are not dropping fast enough to your liking, then you could bump it up to a 1/2, but I would not try 3/4. Just my .2 cents

[bertoni]

I think that slow and steady is safer here. People have reported problems that seem related to sudden, quick changes in the phosphate level.

[rovster]

My tank is about 120. I started with 3/4cup and I'm now at around 1.5C. My phos was never high (highest it registered was 0.08) but I have not been able to get it below 0.04. that said, I have never seen a nitrate reading, so I'm wondering if that is at play. I don't feel comfortable running more than 2 cups at a time both because its expensive, and frankly I think that is excessive. I change it out every month once when it starts creeping up. Like I said, its never been above 0.08 even at the beginning. Yesterday it was at 0.05 and my GFO is a month old. Time to change soon!

[bertoni]

There are cheaper alternatives to GFO, if it comes to that, but the phosphate probably is coming from either food or the live rock. You could look into some lanthanum chloride, if you want to cut costs, but it's a bit riskier and more tedious to dose.

[doctorwhoreefer]

There are cheaper alternatives to GFO, if it comes to that, but the phosphate probably is coming from either food or the live rock. You could look into some lanthanum chloride, if you want to cut costs, but it's a bit riskier and more tedious to dose.

+1

Or look into carbon dosing, then you may be able to eliminate the gfo as well. :bdaysmile:

[Dan_P]

My tank is about 120. I started with 3/4cup and I'm now at around 1.5C. My phos was never high (highest it registered was 0.08) but I have not been able to get it below 0.04. that said, I have never seen a nitrate reading, so I'm wondering if that is at play. I don't feel comfortable running more than 2 cups at a time both because its expensive, and frankly I think that is excessive. I change it out every month once when it starts creeping up. Like I said, its never been above 0.08 even at the beginning. Yesterday it was at 0.05 and my GFO is a month old. Time to change soon!

I assume you are using a reactor, if not that is part of the issue. Another issue with GFO is that it adsorbs less per gram as the concentration becomes low. The curve descrbing the adsorption of phosphate versus the concentration in solution, adsorption isotherm, is fairly horizontal then drops off at low concentrations. Also, if the GFO is not free flowing at the end of the month, the GFO bed may be getting clogged and this is intefering with phosphate adsorption.

Unless you have strong reasons to lower the phosphate concentrations much below 0.03, you probably do not have a phosphate issue anddon't need to use more GFO.

[rovster]

I assume you are using a reactor, if not that is part of the issue. Another issue with GFO is that it adsorbs less per gram as the concentration becomes low. The curve descrbing the adsorption of phosphate versus the concentration in solution, adsorption isotherm, is fairly horizontal then drops off at low concentrations. Also, if the GFO is not free flowing at the end of the month, the GFO bed may be getting clogged and this is intefering with phosphate adsorption.

Unless you have strong reasons to lower the phosphate concentrations much below 0.03, you probably do not have a phosphate issue anddon't need to use more GFO.

I never said I have a phosphate issue ;) That said, my tank is almost exclusively acros and I like to keep my phosphate below 0.05 (not shooting for 0, never have). My reactor is probably way to big for my system so my GFO barely tumbles because of how wide it is. Once a week I invert my reactor (or more put it on its side) to help if there is any clumping. If my phosphate is low I will slow the rate through the reactor and do the opposite if its high. Thanks for the info. I was not aware of that!

[HunterBryan]

will adding to a lot of GFO starting off affect SPS? Because I received my BRS GFO and reactor and I did the recommended dosage and soon after my SPS started STNing and my LPS seemed to be receding

[bertoni]

Some tanks seem to have problems when they get a lot of GFO added at once. I'd start out small and build up, and see how the animals respond.