Can't get nitrates lower than 40ppm even after water changes...options?

[jdircksen]

I've had my 24g nanocube for 1.3 years. For a while, I didn't do water changes as much as I should have and didn't know I was supposed to clean the sponges in the filtration compartments. I've never lost any fish, only 2 shrimp and 2 snails, but I can't be certain they didn't die for reasons other than nitrates. For the past 2 months, I've been trying to get my nitrates down since they were off the charts. I have done 4 40% water changes and my nitrates are still around 40ppm.

What are my options?

I read that a sump/refugium may help, but then the filtration compartments in the nanocube would be wasted space.

Would changing my bulbs affect nitrates? I've been using the original 2x36w 50/50 since day 1.

Any other ideas?

 

[JC VT]

How long has it been since you've cleaned the sponges? You might want to remove them completely and run it without them.

Do you have an algae problem?

I'd remove the sponges, add a skimmer, and do 50% W/C's till you get them down to zilch. Possibly replace or take out the substrate.

 

[jdircksen]

oops, I should have noted that I removed 2 of the sponges. The remaining sponge is in compartment 1 with the charcol sitting on top of it. I clean the sponge weekly. compartment 2 has the heater and some rock rubble. compartment 3 has an MJ 1200.

no algae problems since i first started up the tank using tap water (oops). i've used RO water since then.

 

[sir_dudeguy]

and theres no filter media or bioballs anywhere?

 

[JC VT]

How many fish?

 

[r00onmac]

i know im not addressing your main issue, but i wanna ask about your bulbs...

you run it as a reef or as FOWLR? if its a reef you may want to change those bulbs.. PCs should be replaced AT LEAST once a year and at 1.3 years its a little overdue...

 

[jdircksen]

<a href=showthread.php?s=&postid=8048166#post8048166 target=_blank>Originally posted</a> by sir_dudeguy
and theres no filter media or bioballs anywhere?

i have 1 sponge and 1 bag of charcol.

 

[jdircksen]

<a href=showthread.php?s=&postid=8048254#post8048254 target=_blank>Originally posted</a> by JC VT
How many fish?

valencienna goby, 2 ocellaris, and a valentine puffer. probably 10" woth of fish total.

 

[sir_dudeguy]

try removing that sponge. They can build up nitrates in them pretty quick

 

[JC VT]

I'd guess that it's a combination of not doing w/c's and the sponges trapping detritus. There might be a pile of detritus somewhere in your display, too; I'd check and see if you can find it and siphon it out so it doesn't sit there and decompose on you.

 

[Agu]

Have you had your water tested at the LFS to confirm the test kit readings ?

While you're going there have them test your RO water (with a freshwater test kit) too.