Slightly High Nitrites - Cracked It!

[IanF]

Hi guys - been reading a while, but first post.

I've got a 250L tank with a 100L sump underneath. It contains about 40kg of live rock in the tank and a skimmer in the sump. Water from the wier from the top tank runs down over a column of bioballs, and then through a 2mm thick mat over the top of a 10mm thick bit of sponge, and a second submersed column of bioballs. It's been going about 6 months now.

I've got 4 chromis, 2 clowns and a yellow tang - all still small, plus 3 shrimps, 10 snails and 4 hermits. Also a leather coral and a button polyp - All are doing well and looking good.

The problem is I'm getting a constant low level of nitrite in the water (normally around 0.05ppm - never above 0.1ppm). I'm changing the filter mat on a regular basis - it goes brown and stops passing water after about a week, but so far I haven't done anything with the foam or bioballs. All look a bit encrusted with crud - should I be thinking about a regular cleaning/change schedule for these?

Nitrates are low - about 1ppm, I do a 5% waterchange once a week.

Is there anything I need to look at or think about?

Cheers

Ian

PS - whats the clump of ear shaped things behind the tang? There are a few scattered over the rock - they pick off easily, but I've left this one clump.

 

[J-Money]

i don't remember which it is, but i heard bioballs can add to a nitrite or nitrate problem, so it could be those

 

[CutieWitBooty]

BioBalls are a huge problem and produce alot of nitrates, they break down amm and nitrites really good, but let the nitrates build up, you really need to get rid of them. Also how many gals is a 250 L tank?

 

[bunjiweb]

As for the "frilly thing" have you got any nudibranchs in your tank? i.e. slugs or whatever? Could be an egg ribbon from one of those.

If not its probably a type of macro algae.

I would agree with bio-balls. Manufacturers are very quick to label them as "nitrate removers" but they DO need to be cleaned at least once every couple of months.

Ben

 

[IanF]

Thanks for the help guys.

250L = 66 US gallons
40kg of live rock = 88 pounds
I reckon I've got about 10" of fish, added gradually over the last 4 months

Having spent the afternoon googling bioballs (instead of working) I now understand that they are TOO good at converting nitrites to nitrates, and can lead to high levels of NO3. I'll slowly phase them out.
Am I right in thinking that in theory the balls in the weir that are open to the air do NO2 to NO3, and the submerged balls in the sump do NO3 to N2?

I've removed the foam filter - it was full of brown crud and can't have been doing any good. The thin mat is just as good at removing particulates, and can easily be replaced once a week.

Any other ideas on why nitrites never seem to drop to zero? Can the test kits "go off"? - mine is getting to the end of it's life, and has been stored in a relatively cold damp utility room.

No nudibranchs in the tank - I think the frills are algae type stuff - I just wondered whether they are undesirable in any way? They look pretty good I reckon.....

Ian

 

[Chac]

Personally I'd get shot of teh Bio Balls & let your LR & decent Flow do the Bio Job

 

[Lovesfish]

I need to ask a question here...

I thought high nitrates came from over feeding the fish.

Is that true? IF not, where do they come from?

 

[Fish Fingers]

I need to ask a question here...

I thought high nitrates came from over feeding the fish.

Is that true? IF not, where do they come from?

It comes from waste breaking down, whether it be left over food decaying, fish wee or die off from live rock.

 

[IanF]

My problem is slightly high nitrITE, not nitrATE.

I had an initial spike in the first month when it was cycling, but it has never dropped completely to zero. I've added new fish at the rate of approx 1 a month - am I seeing a lag between new fish and the bacteria population increasing? I have no plans to add any more for the immediate future, so I will continue to monitor.

Ian

 

[IanF]

CRACKED IT!!!!

I have a plastic jug I use for general fish jobs - collecting algae after cleaning, defrosting food, emptying the skimmer cup... AND TAKING WATER SAMPLES!

I did a phosphate measurement total, which I don't normally do - and the reading was off the scale. I took a second water sample directly from the tank, and everything was OK.

So I did a nitrite sample with water straight from the tank - and bingo - virtually zero!

So my problem is that my jug is contaminated!

What a silly mistake to make! Still - that's how we make progress!

Thanks for your help guys - after your advice, I'm going to take the bioballs out at the weekend

Cheers

Ian