Parameter mystery??

I rarely test parameters, as I am a huge water change guy. Tested 8 tanks today, all good as usual EXCEPT my 125 housing a single male Jaguar cichlid. Scored 0 ammonia, 0 nitrite, great... but 0 nitrate?? No other tank showed more than 10. Tested 3 times, its not the test kit. FX5, XP4 and Aquatech 30/60. Canisters havent been touched since late July, both pumping normal and chocked full of bio-max. Tank gets minimum 100% weekly w/c. Fish is doing great, not too concerned, just not getting where the nitrates have gone. Thoughts anyone??

You can have mine if you like.  

Is the 125g planted? That could zap some of the nitrates, obviously large water changes could potentially keep that level quite low.

Beyond that, I suppose I could hypothesize that your nitrate tests (which are fairly inaccurate) are testing low. I think I have read that if you don't shake the nitrate liquid tests very thoroughly (and for extended amounts of time) the results are low readings. I believe the second bottle is the most sensitive to it, as the zinc crystals will settle, sometimes you need to give it a good bash. I've heard of having to shake it for upwards of 3 minutes.

I read a post a little while back that a person could test between 0-40 ppm depending on how shaken the bottle is.

IE one tank might test 5 ppm, but is actually 10, and your 125 gallon might be at 5, but testing 0.

So perhaps all your tanks are testing low.

CanadaAquariaAdmin wrote:Is the 125g planted? That could zap some of the nitrates, obviously large water changes could potentially keep that level quite low.

Beyond that, I suppose I could hypothesize that your nitrate tests (which are fairly inaccurate) are testing low. I think I have read that if you don't shake the nitrate liquid tests very thoroughly (and for extended amounts of time) the results are low readings.   I believe the second bottle is the most sensitive to it, as the zinc crystals will settle, sometimes you need to give it a good bash. I've heard of having to shake it for upwards of 3 minutes.

I read a post a little while back that a person could test between 0-40 ppm depending on how shaken the bottle is.

IE one tank might test 5 ppm, but is actually 10, and your 125 gallon might be at 5, but testing 0.

So perhaps all your tanks are testing low.

No plants in tank, and I am aware of the necessity to shake the crap out of bottle 2.Yes, my large,frequent w/c do make for consistent low readings,thats why I do them. I dont think I'm testing low because the readings on my other tanks are right in line where they historically have always been. Example.. In a 90g I have a single 6in Red Devil with a well established xp4 filter. Nitrate today was 10, maybe a touch more. Reading low would put the actual reading towards 20? I would be very surprised at that. I came across another suggestion. There may be some sludge buildup in the canisters that is acting like a nitrate filter. I clean the mechanical portion about every 3 months, and its been about that long, sooooooo, maybe? I'm more curious than concerned. Always looking to learn. I have just never had zeros in a fully cycled, well established cichlid tank.

I don't think it would even necessarily be 10ppm versus 20ppm. It could be 10 versus 15, or 7 versus 12, the liquid tests aren't all that accurate to begin with. You mentioned not checking parameters frequently, and I know those tests are notorious for testing low after sitting for a while. I've heard that sometimes shaking isn't even enough for the second bottle, but bashing it on a hard surface will dislodge the zinc crystals from the bottle.

I suppose the nitrates could be so low in the tank (2-4 ppm maybe) that the test just isn't picking them up.

I haven't heard of the nitrate sludge filter hypothesis before, I'll have to look it up

At least everything is healthy.

Thx for the reply. Possible the test is a bit off, kit does sit for several weeks between use, and even though I do bang the bottle around, it could still be off. I know the tank is healthy as is the fish. The color chart is a little tough to distinguish, unless dealing with extreme change. Just wanted to post this oddity and see what came up.

Couldn't it just be due to the low stocking level in the tank (i.e. low bioload)? In our 220g we never get readings for nitrate, nitrite, or ammonia, though we get nitrate readings in the other tanks (although even those readings are low, a 'tinge of colour' and never enough colour to match 5); we've been told it is likely due to our low stocking.

Oh sure Shell, single fish and frequent w/c surely keeps it consistently low, but it usually registers something. I have 2 other tanks with single cichlids, and I got readings on those, low as well, but the tube sample of the tank in question was crystal clear, not even a tinge of pink. When I clean the canister sponges this Saturday, then run a test few days after, I will get some indication if the theory of sludge acting as a nitrate filter is indeed viable. I will follow up with a post of my findings

0 nitrates !
This is like 0 trans fat content ! I think the test kits give a certain range of accuracy, so I would think that any value has a +/- range. Like any science experiment I look at trend rather than absolute values. I think you have a very healthy setup.

alexmtl wrote:0 nitrates !
This is like 0 trans fat content ! I think the test kits give a certain range of accuracy, so I would think that any value has a +/- range. Like any science experiment I look at trend rather than absolute values. I think you have a very healthy setup.

Good analogy Alex! I am really wanting to get this guy to monster status, any little quirk with him or his house and I want it addressed instantly, but I am confident all is well, thx for the reply.