240G with 75 sump, WHY do I still have high nitrates?

[VRWC]

Hey everyone...Im perplexed and need some help. I have what I feel is more than adequate filtration, flow etc on a yr old established tank and Im still reading what I consider high nitrates for such small stock & large water column. I havent tested the water directly after a change (I will tomorrow) but after 10-14 days I'm getting between 80-160ppm nitrates.

I feed once a day and sure, I may over feed some, but I didn't think it would be an issue (and by overfeed I mean the food lasts 3-4 minutes instead of them getting it all as soon as it hits the water).

I have a 240g (8x2x2) with the following:

200lbs of eco-complete & black sand, 300lbs of driftwood & rock & approx 30 plants (swords, java fern, moss)

2 x blue acara (3")
3 x threadfin acara (3-4")
2 x honduran red point (3")
3 x Rainbow cichlids (2-3")
3 x polleni (2")
1 x dwarf pike (2")
1 x L082 pleco (3")
15 x corydoras (1-2")
2 x Flagtail Catfish (4")
1 x Thai Catfish (2")
20 x serpae tetras (1")
10 x Buenos Aries Tetras (2-3")

The dual overflows run into a 75g sump underneath the tank at anywhere from 1300-2000gph (depending on what power I set the pump at).

In the 3 chambered sump, it goes through, in order:

filter pad
3" of bioballs
200 scrubbies (submerged)
25 lbs of ceramic rings (koi aquaculture media)
2x Matala High Density Blue Media squares
8 x 18" filter sponges
then to the pump chamber with a Ecotech Vectra L1 DC pump (up to 3100 GPH)


What is going on that I can't keep the nitrates low in this big of a planted tank with this much filtration?
Am I overstocked?
Is it over filtered, not allowing a cycle to maintain itself?

Ive been doing this a long time and have never had this issue, but Ive never done it in anything bigger than a 180 from scratch.

Thanks for any help you guys/gals can give.

 

[Bigfishnut]

Check your nitrate at the source. Some water has nitrate right out of the tap. Also can have ammonia right from the tap as well. Either will cause unusually high nitrates

 

[Bigfishnut]

The other thing...all the filtration in the world won't reduce nitrates. It's the end product in the cycle. The only exception to this is in a reef tank with well established live rock. In freshwater your waterchange schedule dictates your nitrate levels

 

[VRWC]

Check your nitrate at the source. Some water has nitrate right out of the tap. Also can have ammonia right from the tap as well. Either will cause unusually high nitrates

Will do. Ive done it in the past and not had issues but its been years. Thanks for the reminder.

The other thing...all the filtration in the world won't reduce nitrates. It's the end product in the cycle. The only exception to this is in a reef tank with well established live rock. In freshwater your waterchange schedule dictates your nitrate levels

Well if its not in the water coming from the tap, what could be causing it? The plants should be helping with the problem and I don't feel like the stocking is too much, do you?

 

[Bigfishnut]

No, the stocking seems fine. I wonder if all that extra bio media is traping organics and decaying. Seems like an excessive amount of bio to me.

 

[VRWC]

No, the stocking seems fine. I wonder if all that extra bio media is traping organics and decaying. Seems like an excessive amount of bio to me.

So the nitrates from the tap are 5-10ppm...

As for the media, I agree its excessive but my intent was to have enough so that if I got stuck somewhere at work for 3 weeks longer than normal and couldn't make it home, there was enough beni-bacteria to sustain the higher rate etc. There is a sludge buildup on the bottom of the sump about 1/4 inch thick but its nothing that I havent seen in perfectly running sumps & established cycles after years of use.

So, how much would you cut back on the media? Im open to any suggestions that will help.

Ive wondered if its just too over filtered.

 

[Bigfishnut]

I'd start by taking the scrubbies out slowly. Remove 1/10 at a time until gone. Maybe 1/10 per week. I'd guess those are the detritus trapping culprits. Keep that sludge cleaned out also. I try to keep my sumps spotless. Sometimes I even shop vac out all the water and sludge. All your bacteria should be concentrated into one area of bio filtration. It's far more effective that way.

 

[philipraposo1982]

What your water change chedule like?

 

[philipraposo1982]

I have a very strong feeling your just not changing enough water. Either that or dead fish in the tank somewhere.

 

[VRWC]

Ok, so just to be clear, heres how the sump is laid out. Im guessing the Matala pads on the bottom may be holding some waste as well...