mechanical filtration

[t1771]

Hello I am new to the forum, but have had a saltwater fish only tank for 6+ yrs. I have been battling a nitrate problem for a while now and was wondering if anyone had some suggestions...I have a 55 gallon tank, 5 fish, percula & clarkii clown, hawlk, niger trigger and yellow damsel. Not too much. 50 lbs live rock. 1.5-2 inch cc substrate, NO dual lights, remora pro skimmer, 2 powerheads penguin 660's one on each side of the tank, and 2 330 biowheels running with carbon, but no wheels. I am thinking of removing the 330's or at least one of them...hoping it may help with the nitrates. I was also thinking of maybe changing one into a fuge (Nate gave me the idea). What does everyone think? Will the tank be shocked if I stop running the mechanical filtration? Do we think this is part of the NO3 problem?
Any help greatly appreciated..

And by the way..great site!!

 

[NateHanson]

Welcome to the BRS Forums!

The crushed coral could be part of your nitrate problem. It will accumulate a lot of detritus if not constantly vacuumed. I would recommend trading it out for sand as you convert the tank to a reef. I don't think the tank will have any problem if the filters are removed. Adding some LR would probably be a good idea too.

Nate

 

[clamm]

how big is the niger trigger, could it alone cause it in a 55 if its a med-adult sized. have to ask.

 

[Fingolfin]

I have a 55 gallon tank, 5 fish, percula & clarkii clown, hawlk, niger trigger and yellow damsel. Not too much. 50 lbs live rock. 1.5-2 inch cc substrate, NO dual lights, remora pro skimmer, 2 powerheads penguin 660's one on each side of the tank, and 2 330 biowheels running with carbon, but no wheels. I am thinking of removing the 330's or at least one of them...hoping it may help with the nitrates. I was also thinking of maybe changing one into a fuge (Nate gave me the idea). What does everyone think? Will the tank be shocked if I stop running the mechanical filtration? Do we think this is part of the NO3 problem?
Any help greatly appreciated..

And by the way..great site!!

Please go ahead removing the biowheels. Bio-media is a nitrate sink.

Fuge is a good alternative. I would add lots of sponges in it.

 

[RichConley]

He says he took the wheels out...so these are just HOB filters with no media but carbon. THey just increase waterflow....I'd leave em, they can't hurt.

 

[MarkO]

Cut down on your bioload and turn the 330 into a refuge. Add some caulerpa and put a 10 watt fluorescent light over it. I bet when the detritus goes away, your nitrates will too.

 

[t1771]

the niger trigger is only 2 inches tops...he's a baby, just got him. In the past I have had excellent results with triggers.
Yes I did take out the bio wheels..actually I never really ran the filters with wheels for saltwater. As for the 330's I am thinking maybe keep one as is and make the other into a fuge.Any suggestions on how to go about this.
I have had sand in the past Nate, but my problem has always been the sand getting stuck in the impellers on my 330's. My clarkii loves to kick it up with his tail and then the filter grinds. Not too long ago (maybe 6 months) completly changed over to sand and then back to cc in a day. The impellers are VERY touchy.
Any more feedback.... thanks in advance

PS - I'm a 'she' not a 'he', RichConley...lol

~Tiffany

 

[t1771]

One more thing....Nate u don't think the 50 lbs of LR is enough?!?!

 

[NateHanson]

In my 65g, I've got about 80 pounds of Fiji and Kaelini rock (less dense than Fiji), and I'd say my tank has less rock than most of the tanks I see. I think people aim for about 1.5 pounds per gallon, give or take. Beyond that it's aesthetic preference.

 

[wsonner]

the niger trigger is only 2 inches tops...he's a baby, just got him. In the past I have had excellent results with triggers.
Yes I did take out the bio wheels..actually I never really ran the filters with wheels for saltwater. As for the 330's I am thinking maybe keep one as is and make the other into a fuge.Any suggestions on how to go about this.
I have had sand in the past Nate, but my problem has always been the sand getting stuck in the impellers on my 330's. My clarkii loves to kick it up with his tail and then the filter grinds. Not too long ago (maybe 6 months) completly changed over to sand and then back to cc in a day. The impellers are VERY touchy.
Any more feedback.... thanks in advance

PS - I'm a 'she' not a 'he', RichConley...lol

~Tiffany

IMO you would get much more benefit from the sand and getting rid of 330's altogether. With a 4" DSB you could run your tank very well with JUST live rock and your Remora Pro...though I recommend the AquaC pre-skimmer as it SIGNIFICANTLY increases skimmate production.

Wes

 

[t1771]

I have the prefilter i just have been too lazy to put it on the skimmer...if i was to remove the cc and switch to sand, I woudl have to dismantle the entire tank right? wouldn't that cause the tank to recycle?

 

[wsonner]

I have the prefilter i just have been too lazy to put it on the skimmer...if i was to remove the cc and switch to sand, I woudl have to dismantle the entire tank right? wouldn't that cause the tank to recycle?

That would definitely be a disruption to the tank. Not an easy task for sure. I've never done this but in thinking about it I might just remove a good portion of the crushed coral and put aragonite/southdown on top of what's left. Anyone think that would be a problem? As far as a cycle goes, I'm sure you will take some hit but your live rock is the major bio filter here so I doubt it will be too harmful. Anyone? Thoughts?

Wes

 

[t1771]

i made the change over about 8 months ago. basically syphoned out cc sections at a time and replaced it with sand. But that lasted a day, b/c one of my clowns loves to dig and kept kickign up sand, so it got stuck in the impellers on the 330's....but if i am getting rid of the 330's there shouldn't be a problem. How do I know the LR isn't causing the nitrate problem?

 

[wsonner]

i made the change over about 8 months ago. basically syphoned out cc sections at a time and replaced it with sand. But that lasted a day, b/c one of my clowns loves to dig and kept kickign up sand, so it got stuck in the impellers on the 330's....but if i am getting rid of the 330's there shouldn't be a problem. How do I know the LR isn't causing the nitrate problem?

LR only contributes to nitrate indirectly...that is...since it is acting as your biological filter (assuming it has been in there a while and totally cycled) then it is converting your waste into nitrate. LR also helps denitrify because it usually has many pockets for growing the anerobic bacteria required for denitrification. The things that contribute to nitrate build-up are: heavy bio load, over feeding, lack of water changes and inadequate skimming. Short of a denitrifying deep sand bed and/or sufficient LR the only real ways to reduce nitrate are water changes and heavy skimming. I can't preach more strongly about the benefits of a good deep sand bed of oolitic aragonite for denitrification. It sounds like you have a great skimmer in the Remora Pro. Maybe you need to tweak it. How much skimmate do you get daily? You said you did do the switch over to sand. What type of sand did you use? How deep is it on average? Again, nitrate build up is due to bio load and over feeding. Those are really the only ways it can get there (unless your source water contains it to begin with). I hope this helps.

Wes

 

[t1771]

i did do the switch over but replaced the sand with cc within a day. I only recently started using the remora pro, i have been getting green skimmate about 1/2 inch a day...haven't realyl measured it with a ruler.

 

[NateHanson]

Hey Tiffany,
Sounds like your skimmer is working well. Personally I'd go ahead and siphon/scoop out as much CC as you can, and cover the rest with fine sand. I think the crushed coral is where all your nitrates are coming from. Bacteria grow on the surface of the substrate particles (and on everything else in the tank) and those bacteria convert ammonia waste into nitrite, then nitrate. Another kind of bacteria can convert the nitrate to nitrogen gas (which just blows off into the air), but those bacteria require a low oxygen environment. If your crushed coral is course it will have too much water space between particles, and won't develop any microaerophilic areas where the last step can occur. In addition, detritus settles into all the space betwen the crushed coral, and this combination could produce a lot of unwanted nitrates. Since you've got a good skimmer, live rock, and a moderate fish load, I think the crushed coral is a very likely source of your nitrate problem. Either thoroughly vacuum your crushed coral regularly, or replace it with at least 3 inches of fine sand.

By the way, have you told us what your nitrate readings are. Can you give us a number so we have a better idea of your situation?

Cheers,
Nate

 

[wsonner]

Hey Tiffany,
Sounds like your skimmer is working well. Personally I'd go ahead and siphon/scoop out as much CC as you can, and cover the rest with fine sand. I think the crushed coral is where all your nitrates are coming from. Bacteria grow on the surface of the substrate particles (and on everything else in the tank) and those bacteria convert ammonia waste into nitrite, then nitrate. Another kind of bacteria can convert the nitrate to nitrogen gas (which just blows off into the air), but those bacteria require a low oxygen environment. If your crushed coral is course it will have too much water space between particles, and won't develop any microaerophilic areas where the last step can occur. In addition, detritus settles into all the space betwen the crushed coral, and this combination could produce a lot of unwanted nitrates. Since you've got a good skimmer, live rock, and a moderate fish load, I think the crushed coral is a very likely source of your nitrate problem. Either thoroughly vacuum your crushed coral regularly, or replace it with at least 3 inches of fine sand.

By the way, have you told us what your nitrate readings are. Can you give us a number so we have a better idea of your situation?

Cheers,
Nate

Nate, with ALL due respect, I only differ with you on the idea that nitrate comes from the crushed coral. It only does so inasmuch as it comes from any other part of the biological filter. It is a closed system so that even if this were a bare bottom tank the nitrate level SHOULD be close to the same as it is now (since the LR or other parts of the bio filter would simply ramp up to handle the same bio load, thus the nitrate output should be close to the same) short of some sort of export mechanism. So the place to attack this is by reducing feeding, reducing bio-load and increasing water changes OR by finding another means of exporting nitrate through an effective DSB etc. Probably symantecs...