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Anonymous
dear 4chan,

my nitrite levels are consistently testing too high. i perform a 25% water change every time they test high. i have a corner box filter that i have had running for a month. i have washed the debris off the GAC itself. why are my nitrites so high, and how often should i change the cartridge in my box filter?

p.s. freshwater 10-gallon tank, 7 cherry shrimp, 4 neon tetras and 4 corys.
>> Anonymous
you should never change the cartridge at all.
There should be bacteria growing in the sponge or whatever your filter contains, that will break down the nitrite.
That's the whole point of the filter.
If it gets clogged so that water stops flowing, you can wash part of the filter cartridge carefully.
A big box filter will have separate levels, so you can wash one level, while the others are untouched and thus can still function.
>> Anonymous
A good filter will also have a level of cotton wool that can and should be exchanged in every week or so, cause it will filter very small particles and gets clogged very fast.
>> Anonymous
granular activated carbon.
>> Anonymous
Get a box filter with sponges.
>> Anonymous
>>203167
Week? More like month for me. And not changed, but washed. I change it after every 2-3 washes. But honestly it all depends on ammount of dirt your tank generates.
>>203168
Carbon is a waste of money, get sponge.
>>203161
Hey op, do you have plants? Plants love nitrites. Healthy plant population would eat more nitrite and ammonia then your biofilter.
Plus this is only 1 month old setup, your cycling is not finished yet. I believe you have too many fish for tank that young and that small. No worries though, keep doing waterchange, add some plants, do not overclean your filter and sit tightly on your ass. BTW, you never clean filter in tap water, use your aquarium water. Chlorine and/or chloramine in tap water would kill bacterias instantly.
>> Anonymous
OP here. i do have plants. i have two fairly large hornwort bunches. i know the shitty incandescent lightbulb i have in the hood is not adequate for plant growth, but it has sustained them without much browning in combination with indirect sunlight. hornworts are low-light anyway.

i was considering adding more tetras for a school, maybe 4 more, but i think that would stress it too much.

i don't think it's too packed as is, but for the amount of maintenance i think i will just keep what i have. the shrimp are very low-stress and because of them i haven't had to worry about algae at all.
>> Anonymous
I worked in aquarium maintenance.

Anyway, so, you shouldn't have even added shrimp to your setup until your tank was fully cycled, which can often take a month or more. Your little tank is way overleaded for being so young, but there is little you can do about that now, so here's what you -can- do.

Ammonia -> Nitrite -> Nitrate -> Cycled. This is your standard process, and as you can see, you're smack in the middle of it. I would suggest Laying off on the water changes and paying a visit to your local petstore. In a section of refrigerated foods (ask an employee) there will be a product called "Bio-Spira," which will come in the appropriate size 35 gal. and under. This is cultured bacteria that will supposedly cycle your tank over night, but I believe it takes a few days. If you want to try this, go on ahead, but there are obvious risks, such as shocking your fish from their usual nitrite-filled environment; however, it could very well work wonders.

When you rinse your cartridge, I hope you're dechlorinating the water you're doing it in. If not, that's part of the problem. Try these steps. <3