How much GFO 180G

[gregdepot]

My 180 has been set up about 5 week.
3 weeks in it had 6.8 Nitrates, it now has 0 nitrates. Feeding 8 small to medium (some will grow much larger) fish twice a day. I used tap water and topping off with tap water and have not done a water change, last time I check Alkalinity was 15.5 DKH due to the tap water used. My Phospates are at .69, since my Nitrates are zero after feeding a fair bit for 5 weeks, it seems like GFO maybe helpful?. I have some bags for carbon and ordered the BRS mini reactor. That said the BRS calculator for a 190-200 gallon system volume states I need 3 cups of GFO which seems kind of extreme to me, but they also arn’t doing it for full time use. I was thinking a smaller amount full time if that would work?

i might switch to RO/DI later on but curious where tap water will take me.

 

[dwest]

My 180 has been set up about 5 week.
3 weeks in it had 6.8 Nitrates, it now has 0 nitrates. Feeding 8 small to medium (some will grow much larger) fish twice a day. I used tap water and topping off with tap water and have not done a water change, last time I check Alkalinity was 15.5 DKH due to the tap water used. My Phospates are at .69, since my Nitrates are zero after feeding a fair bit for 5 weeks, it seems like GFO maybe helpful?. I have some bags for carbon and ordered the BRS mini reactor. That said the BRS calculator for a 190-200 gallon system volume states I need 3 cups of GFO which seems kind of extreme to me, but they also arn’t doing it for full time use. I was thinking a smaller amount full time if that would work?

i might switch to RO/DI later on but curious where tap water will take me.

I think you are smart to question the amount of GFO. In fact, I wouldn’t use any at the moment. I would let your tank mature. As it does you should start seeing measurable nitrates. if not, I would consider dosing nitrates.

You probably don’t want to hear this, but switching to RODI water now is a good idea as well.

 

[thomas_neil]

My 180 has been set up about 5 week.
3 weeks in it had 6.8 Nitrates, it now has 0 nitrates. Feeding 8 small to medium (some will grow much larger) fish twice a day. I used tap water and topping off with tap water and have not done a water change, last time I check Alkalinity was 15.5 DKH due to the tap water used. My Phospates are at .69, since my Nitrates are zero after feeding a fair bit for 5 weeks, it seems like GFO maybe helpful?. I have some bags for carbon and ordered the BRS mini reactor. That said the BRS calculator for a 190-200 gallon system volume states I need 3 cups of GFO which seems kind of extreme to me, but they also arn’t doing it for full time use. I was thinking a smaller amount full time if that would work?

i might switch to RO/DI later on but curious where tap water will take me.

I would def switch to ro/di sooner rather than later. Tap water can have a lot of chemicals and solids in it like rust and stuff that are very bad for coral health. DKH of 15 is very high and will be hard to keep stable with dosing

As for the GFO I run a 1/4 for every cup of carbon for long term. Just mix it together so the gfo doesn’t stick together with the lower flow you run for carbon. You can adjust as needed for your particular needs on your tank. I’d personally start with less and slowly add more over a couple weeks. Don’t want to swing the tank to much.

Id also watch your nitrates bottoming out, I let my tank bottom out once and got Dino’s from it. Dosing Red Sea AB+ really helped get my nitrates up and feeding 3 times a day.

 

[gregdepot]

I think you are smart to question the amount of GFO. In fact, I wouldn’t use any at the moment. I would let your tank mature. As it does you should start seeing measurable nitrates. if not, I would consider dosing nitrates.

You probably don’t want to hear this, but switching to RODI water now is a good idea as well.

I own a RODI but have never used it, but I have it so could go to that just seeing what the limits are for tap water. To be more clear the sump and 1/3 of the rock were setup already on a 36 gallon tank while I got the 180 ready so were established up to 6 months, the other 2/3 of rock was in a 55 gallon and ghost fed and some of that rock was used, this rock was doses with Start XLM and Microbacter Clean


its possible the old rock or tap has phosphates still.

i have about 150lbs of rock, 20lbs of sand, a Brightwell Block, Bubble Magnus Curve 7 Skimmer, and a small amount of Chaeto in fuge.

the Nitrates went to 6.8 then to zero without water changes, other then detritus collecting more the tank is more established then most I feel for being “5 weeks” old. I could be wrong but I think system seems to be taking care of nitrates.

 

[gregdepot]

I would def switch to ro/di sooner rather than later. Tap water can have a lot of chemicals and solids in it like rust and stuff that are very bad for coral health. DKH of 15 is very high and will be hard to keep stable with dosing

As for the GFO I run a 1/4 for every cup of carbon for long term. Just mix it together so the gfo doesn’t stick together with the lower flow you run for carbon. You can adjust as needed for your particular needs on your tank. I’d personally start with less and slowly add more over a couple weeks. Don’t want to swing the tank to much.

Id also watch your nitrates bottoming out, I let my tank bottom out once and got Dino’s from it. Dosing Red Sea AB+ really helped get my nitrates up and feeding 3 times a day.

the goal with high DKH tap is to try and avoid dosing, but yes may need to use RODI.