Nitrates high

[PopeShawnPaul]

Crazy. I put this in here because I think it's more appropriate. I've had a FOWLR for about 6 years now, no sump, with a bak pak skimmer. My nitrates have always been less than 5 ppm. Now all the sudden I did my first nitrate test in over 2 years, and the test is indicating 80-160 ppm. Crazy. Yet I have had 4 healthy fish for over 4 years, including my yellow tang. I don't think this is possible.

I'm going to buy a new test kit tomorrow, and I am doing a 50 percent water change. I don't overfeed. However, my bio stone things that came with my fluval are about 4 years old. I'm guessing they are getting clogged and causing the problem. I didn't think fish could survive with nitrate levels that high, so I'm guessing my test kit is off. Any other ideas/suggestions?

 

[taikonaut]

The water change is going to help. Yeah, it is surprisingly high for a FOWLR setup... :?

To clean the bioballs/stones (should not do this unless absolutely necessary, BTW), put the balls in a clean bucket with the old tank water. put lid on the bucket and shake to loosen the dirt. Be very careful and monitor the ammonia/N/N afterward since this "cleaning" will get rid of the bacteria on the balls and can cause a deadly ammonia. Some people do it to half of the bioball at a time instead of all of them to alleviate this danger.

 

[c0yote]

I believe fish can accomodate these high levels if the nitrates rise gradually. Sounds like the nitrates have been rising from the dirty media in the filter.

Went back and checked a lot of old messages a few weeks back - nearly every post with a subject of high nitrate levels is from a tank with a canister filter and a crushed coral substrate.

I've got a similar setup (4 yr old 60G FOWLR) - one thing I did was to remove the bio-stones from my Fluval and let my liverock handle the bio chores (currently very light fish load w/ a mated pair of yellow shrimp gobies & a false percula, 50 lbs of LR). Just added some more lighting and a couple mushrooms & star polyps - doing fine so far.

 

[Anonymous]

i agree with coyote....you prob shouldn't do a 50 percent change....that kinds of a knee-jerk reaction that may not be necessary....i would buy a new test kit first...because they do go bad after a bit....i would think especially so if they get too hot or too cold...

 

[Jolieve]

Agreed with everything these guys have said so far... except I will go one step farther. If you are not willing to remove those biostones once a week and give them a good rinse in water before replacing them in the fluval, just take them out of the fluval and run other media that you will regularly (once a week or so) replace.

Those ceramic stones, along with "bioballs" and "biowheels" are really better left to freshwater tanks where build up of nitrates are much less of an issue for the livestock. These sorts of things need regular maintenance if you are going to use them. If you don't want the maintenance, just leave them out, it won't hurt anything in your tank and it will save you some work.

Also, what Abu said. Start by removing those biostones, and then do much smaller water changes to reduce the nitrates gradually. Seems like your fish are pretty tough customers if they have survived this so far... best to be gentle to their systems and take it slow and steady. 20% would be the largest water change I'd recommend... and that may be a bit generous.

Good luck!
J.

 

[ChrisRD]

I agree with most of what has been said except regarding the water changes. If you do the math, small water changes are not going to be very effective at reducing nitrates. A series of 50% water changes - say one every few days for maybe 3 or 4 total would really help get things back on course. If water changes are done correctly (ie. careful matching of temperature, salinity, pH, etc.) no harm will come from doing a large water change.

 

[PopeShawnPaul]

To update:

My test kit was bad. My nitrates were not 160 ppm. They were 40 ppm. However, this still scares me considering I have a few inverts in the tank. I did do two 30% water changes, and my nitrates are now about 10ppm. I took out the Fluval and the ceramic stones (it was originally only used for carbon runs, but i kept it on recently 24/7). I only had two medium sized power-heads, so I ordered 3 mag-1200's. Back when I had no nitrates ever, I had lots of water current. I'm imagining that more water movement with my 50+ lbs of live rock should do it.

This all makes sense to me now. In the last few months, I noticed my yellow tang that I've had for 6 years started to get signs of HLLE. I fed him a mixed diet and he always got plenty of veggies and nutrients, so i couldn't understand why. I'm guessing the nitrates started going up about 3 months ago as the Fluval became clogged and I didn't do water changes. This stressed him out, and the HLLE started. There is no other answer because I've been feeding him a lot of veggies, selcon soaked food, nori sheets daily, etc.

I remember years ago I tried to grow various macro-algaes in my tank. The problem was, my tank was always too clean we found out. With such a tiny bioload, I never had any nitrates. The macros would just not grow ever, despite water changes, plenty of light, etc. I never even had algae grow in my tank. I'm thinking of trying some macros now, I know my tang would like it...

I learn something new every year in this hobby. Always do water changes and replace old and broken powerheads.

 

[Jolieve]

Yes... sorry to say my friend, you've got to keep up on the water changes and maintenance no matter how well established your tank gets.

Good luck with this!
J.

 

[DK]

Unless you have a way to export nitrate, those levels are going to be a normal occurance......... if you want happy fat fish. The Nitrate levels probably are in the 80 to 100 range and probably don't matter that much in the FOWLR setup. You can always get a denitrator and add that to the system.

I do a water change for mine with the water from my reef system. I measure 0 from the reef water but 30 to 110 in the FOWLR. The fish are happy!!!.....and always hungry.

 

[Anonymous]

This is why I do not use cannister filters anymoe. I have never had a problem with Nitrates since then. Mine are always 0.