GFO Reactors and media type

[jwilson]

I was researching the GFO reactors brands and media. Based on reports of the LTF leaking, and the cost of the NextReef reactors I am leaning toward the BRS reactor.

I also read that some folks seem to think that the High Capacity GFO from BRS doesn't work as well as the regular GFO.

Based on the instructions at BRS at my total water volume of ~140 gallons (DT, Sump, fuge, etc) I need 2.2 cups of HC. The reactor holds 2 cups. So my questions are:

1.) for about 140 gal of water would you get the regular size or jumbo reactor?

2.) what are your opinions on the HC vs. regular GFO?

Right now I'm figuring on the regular size and std GFO and then I can either change at greater frequency or switch to HC depending on how quickly it looses effectiveness. That seems better than running 2 reactors for the same media.

Also - their instructions say "For Granular and Pellet GFO start with 1 tablespoon per 4 gallons of water (16 tbsp = 1 cup). After 4-8 weeks the aquarium will have adjusted to lower nutrient levels and the amount of GFO can be increased up to 2 tablespoons per 4 gallons of water."

Can anyone explain the above "aquarium adjusts" statement? It would seem to me that "GFO becomes less effective" is more plausible but they just don't want to say that. They also say to replace in 4-8 weeks as PO4 levels go up/algae grows. So are they expecting/suggesting reefers put in GFO, then add more in 4-8 weeks and then replace all in another 4-8 weeks. Sorry but this seems a bit weird. Add GFO, monitor, replace when PO4 rises to user determined threshold(assuming all other things remain equal) or time has passed makes the most sense to me.

3.) What practice do you guys use?

Thanks.

 

[downbeach]

If you used the reef calculator, you may have selected the wrong supplement. I use the BRS (regular) reactor with the HC in a 180, and it only calls for 1.41 cups. All systems are different, but I replace mine every 9 to 10 weeks. I only change it when my PO4 levels start to go back up. I would get a Hanna checker for this test, since most of the chemical kits are considered less accurate.

 

[jwilson]

I used their instructions
For Granular and Pellet GFO start with 1 tablespoon per 4 gallons of water (16 tbsp = 1 cup). After 4-8 weeks the aquarium will have adjusted to lower nutrient levels and the amount of GFO can be increased up to 2 tablespoons per 4 gallons of water. For HC GFO start with 1 tablespoon per 8 gallons of water (16 tbsp = 1 cup). After 4-8 weeks the aquarium will have adjusted to the low nutrient level and the amount of GFO can be increased up to 2 tablespoons per 8 gallons of water. Change all three types of GFO when phosphate levels rise or algae growth becomes visible (4-8 weeks).

I just checked and their calculator comes up with the same as the "starting" amount so in that case I could use the regular size and standard GFO as I planned. I guess I can just chalk it up to their directions being a bit confusing, or me over-thinking it too much.

Thanks for the tip on the Hannah checker.

 

[downbeach]

I think if you're the type of person who would rather work on a regiment of just doing monthly changes, then just get the standard GFO and change your GAC at the same time. If you are going to change it based on your test kit readings, then you should go with the HC, since it will last longer with less media.

 

[jwilson]

How about I'm the type of person that would do both - . I'll start by changing based on readings, then over time figure that I should change every X-days, but continue readings and change at every X-days unless the readings indicate needing it sooner. Thanks Jim

 

[TanksNStuff]

Keep in mind that these calculators / suggested amounts are based on water volume, not what the tank can hold. Your live rock will displace a fair amount of water so you have to deduct some gallons for the rock when determining your "volume". Also, since sumps usually have baffles and are not completely full, you need to figure out what to deduct there too. I suggest you keep track of how much water you put in when you first fill up your tank/sump so you have a good idea of actual volume.

As for the directions and why they say to add in more later... what they mean is don't start with the full amount suggested. A system without GFO can go through a quick change when adding in the recommended amount of GFO all at once. It's better to use about half the amount, let your tank adjust to the nutrient reduction, then add more in as neccessary. Bottom line, you don't want to shock your system with a huge swing.

Your fish and corals have tried to adjust to the slowly increasing nutrient levels, but they can't adjust to a sudden depletion of them. It's ok to have a big correction if your phosphate is super high and at dangerous levels already. But even then you still want to correct it in chunks and not all at once.

Since you'll likely be doing this at the first sign of increasing phosphates, you want to use the "half" amount and see how that does. If it doesn't remove all your phosphates, then increase as needed... but not more than the recommended amount. If you need more than the recommended amount, then you should be looking towards big water changes first, GFO (or other means) second.

One other tip... run some tests on your new salt water you makeup, before filling the tank or doing a water change. Sometimes you can get a bad batch (or be using poorly filtered RO water) that is already high in phosphates and doing water changes actually worsen the problem instead of correct it.

I've only used high capacity (fines) GFO, so can't comment on that vs. pellets.

 

[jwilson]

Thanks George that makes perfect sense.