Help with tank readings

[6044jason]

Hi all,

Had my new tank running for 7 months now, all the rock was cured for 4 weeks by me.

I can't get my nitrates below around 40ppm.

It's a 120g (400lts) tank with 40g sump, i'm running a skimmer, GFO reactor (as phosphates were at 0.25 but now lower than 0.1 and dropping) Biopellet reactor which has been running for 12 weeks, pellets are in constant tumble and the outlet is by the inlet of the skimmer.

My reading are as follows:

Alk:9.1
Calcium:425
Mag:1215
Salinity:1.025
PH:8.2
Phosphates 0.1
Nitrite: 0
Ammonia: 0
Nitrates: 40

Stock is:
Fireball angel
2 x clowns
foxface
sailfin tang
power brown tang
2 x wrasse
algae blenny


I have minimal nuisance algae, just a glass clean once every few days.
Sump turnover is around 4x per hour with a total flow of 22x per hour.

I change 50ltrs every 2 weeks.

Any ideas? does the biopellet reactor look set up correctly from the photo?

 

[Conchman]

Little more information. Type of test kit? Some measurements seem elevated, maybe false? Verify with a second method. Any changes in the setup recently?

 

[lapin]

Quick questions. Do they drop after a water change? If so how long before they come back up? Have you tried a bigger water change?

 

[bertoni]

None of the animals that I could see in the photo will be affected by 40 ppm of nitrate, so you could just ignore it. I suspect that the tank is limited for denitrification by the amount of live rock. It's possible that more bio-pellets might help, too, since they likely are surface-area-limited, too.

I agree with getting a second opinion on the test kit before spending a lot of money or doing anything drastic. Kits seem to fail fairly frequently.

 

[mcgyvr]

Totally normal IMO..
Tanks/bacteria from my experience take a good 8+ months to get that good anaerobic bacteria (denitrifying bacteria) well established..
And as you have had elevated phosphate levels that may indicate an overfeeding situation which isn't helping..

The "nitrifying" bacteria gets established rather quickly and is mostly surface dwelling.. The "denitrifying" bacteria develops in low oxygen areas and can take a while to get established..
Its the denitrifying bacteria that really does the big work of converting nitrates to nitrogen gas..

I also feel that biopellets can take a while to get established and are not as effective as liquid carbon dosing using vinegar or vodka,etc...

As stated the fish really won't care about those nitrate levels and as long as you aren't having real nuisance algae problems then its not something you need to be overly concerned about..

Give it more time and see how it goes..
Adding some more rock can help too depending on how much you have there..
Maybe even try liquid carbon dosing instead of the biopellets..

Are they even dissolving and needing to be replaced fairly frequently (every months or so you should see a clear reduction in the amount/size of pellets in there)