View Full Version : nitrate problem in 500g reef tank
01/22/2006, 11:08 AM
Hi, I just combined my 125 and 75 gallon tanks into a 500 gallon....so really my tanks have been around for years and the only new thing is 300 gallons of new water. anyway, ever since the tank has been set up I have had a nitrate issue. It's been 3-4 weeks now and it started on the lower level of OKAY on the chart. Now its in the lower level of the unsafe zone. Previous advice from other posts were to get a sump. Anyway, I not only have a sump now but a larger tank, 300 lbs of live rock, about 10 reef fish, 1 zebra moray, 1 brownbanded shark, and a huge clean up crew consisting of snails, crabs, cucumbers, star fish, etc. I feed 1 small cube of frozen food daily sometimes skipping a day. any ideas as to why my nitrates are high? Thanks in advance.
01/22/2006, 11:23 AM
Well, for one you need more live rock. You need at least 500lbs
Second, do you have a good skimmer? Do you run carbon and or phosguard?
01/22/2006, 11:32 AM
I am not sure if the fish load is big enough to spike the No3 levels that high. It could be the turning of the sand during the transfer? Could there have been some death during the transfer(live rock, sand). Water changes are tuff on such big tanks. I have a system that contains @ 400 gals with fuge and sump. I just completed a 125 gal water change. WOW!! But the No3 level before the change .05 to 1 day after the water change almost undectable. Hopefully you have a large fuge with tons of macro for nutrient export. Good luck
01/22/2006, 03:00 PM
First thing I would do is get a new test kit. Often the reagents go bad, and there are plenty of other things in the water that can interact with the tests to make nitrates read falsely high (or falsely low).
What are the 10 "reef fish" you have? Sharks and morays tend to make a lot of waste, so that can certainly be contributing to it. If some of those other fish are big waste producers, that could certainly be the cause. However, overall this shouldn't spike it that high in that short a time in a tank that size. I agree with dustin that things dying off from the transfer is probably contributing.
300# should be plenty for a tank that size, as long as it's not stocked to heavily.
Do you have any system to reduce nitrate? Large pieces of LR, DSB, refugium, mud filter, etc are some of the possible methods for this.
I have a 46g tank with a DSB; I feed more food than that in a day. My nitrates were undetectable the last time I tested.
01/22/2006, 10:36 PM
I'm hoping its the transfer because I have a similar issue. My Nitrates have been at 0 in my 180 for over a year. I just upgraded my refugium from a 20 long to a 75 and now my Nitrates are hanging around 10-15. I'm guessing its just the sand and rock rubble being turned over and causing a spike so I'm gonna let it ride for another week or two.
01/23/2006, 07:25 AM
thanks for all the info. I really hope it's just the transfer, but i would have thought by now it would have settled. I'm not looking forward to my first huge water change to see if it helps. My reef fish are yellow/sailfin tang, chromis, lemon peel, goby, and a couple i dont know the names of. The eel only eats once or twice a week so i didnt think he could contribute much to the waste...and the shark, well i never see him so he's never really fed by me, thus i assume he's not contributing much either. My skimmer is huge but i dont know what kind it is, it came with my setup. As for the sump, it has bio balls. I havent tried any carbon or phosgaurd but if you think it will help i could try it.
01/23/2006, 07:36 AM
Ah ha! I would start to remove the Bioballs a little at a time
01/23/2006, 08:13 AM
why is that? unfortunately i dont think i have access to them because they built my stand around it and i cant pull the box out. atleast i dont see anyway to get to it. also, i am new to the whole sump thing so i assume they are called bio-balls. they are the little black balls with spikes on them...bio-balls right?
01/23/2006, 12:03 PM
yeah, those are the bio balls, there are so effecient at breaking down waste that they become "nitrate factories." You should definetly start removing some everyday until you have none in there. The 300lbs of LR should easily handle the bio-load of your tank, if not, you can eventually place some more LR in the sump where the bio-balls used to be.
01/23/2006, 12:39 PM
so are you saying that with a little more live rock i wont even need the sump then? is it still ok to run it without the bioballs so i can still have the circulation and a place to keep the heater, skimmer, etc? i sure hope i can find a way to get them out. assuming i cant since my stand was built around it, is there any other way to keep the nitrates down?
01/23/2006, 01:59 PM
you could increase skimming, add macro algae to the sump we just need more export. Placing a deep sand bed live rock and macro in a refugium or sump. Just ideas.
01/23/2006, 02:46 PM
if i cant get to the bio balls can i put the macro algae in a different chamber? also can i just add more live rock and deeper sand bed to the tank instead of sump to help?
I will stay off of the bioball/nitrate discussion for the most part. Just don't think that removing all of the bio balls is going to be a silver bullet.
What is your water change schedule?
I would also recommend a new test kit (like a salifert) if your old one is too old.
01/23/2006, 04:19 PM
well, its only been up for 3 weeks or so now so i havent done one yet. i was hoping to go 6 weeks or so because i was told with the sump and LR combo, i shouldnt have to do as frequent of water changes.
01/23/2006, 11:58 PM
I would be prepairing to complete a nice sized water change. The No3 will in time lower due to the live rock and sand. But you can expidite the export with water changes. If you have a camera handy or cell phone camera snap us a shot of your sump and we can see if we can help you with macro in the proper chamber.
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