nitrite emergency

[30gal4fish]

i have a 30 gal tank with 50 lb LR
one clown fish, 2 damssels, one lown more blenny and one angel fish (the one with the black line on the bottom)
i also have a start fish and 2 anemonies with 4 sponges.
my amonia is 0
but my nitrite is 5 it has never been so high.
i have not done anything different to the water.
i feed them pellets and frozen cubes.
i did a water change like a week ago. (2 gal)
the salinity is at 1.026
nitrate is 10
the fish are acting normal.
what do i do, my red blod shrimp is dying as i write.
i added 10 hermit crabs (tiny) like a week ago with the blenny.
and everything was normal until today. the other fish are eating normal
ph is 7.9
i know anemonies dont tolerate bad water but they are perfectly healty
so i dont know whats going on. ive had this tank for a year already.
please help.

 

[30gal4fish]

i test the nitrite wrong, it was 0.25 the calcium was 500
i dont know what i did to change the water so drasticly. i just hope i have not kill my fish by tomorrow morning. any advise will help.
after this, i did a water change of 5 gal, and salinity went to 1.021

 

[30gal4fish]

one questions, there are two filters that i buy for my magnun 350
the soft one that goes around and the hard one that goes inside. how often do i suppose to change the inside one and how do i suppose to clean it.
i just read something that is probably what i am doing wrong but i just want to make sure.
please advise.

 

[mikeyjer]

Originally Posted by 30gal4fish
i test the nitrite wrong, it was 0.25 the calcium was 500
i dont know what i did to change the water so drasticly. i just hope i have not kill my fish by tomorrow morning. any advise will help.
after this, i did a water change of 5 gal, and salinity went to 1.021
Such a drastic salinity change will shock your inhabitants!!!! Not a good thing to do, did you test your salinity level in the premixed water???? Did you let the premixed water aerate over night? I would try to bring the salinity level back up. I just hope it's not too late.... :scared:

 

[30gal4fish]

i just want to know how often do i change the cartrige inside.
and how often should i feed my fish, because i feed them every day and apparently that is bringing the nitrate up.
should i use prime once in a while? or that is just for starting up the tank

 

[kzoo]

Man your bioload is high you need to stop buying fish or get a bigger tank. How old is this tank?

 

[shu-perman]

With the amount of bioload you have I would do 3 gal water changes 2x's a week(like every 4th day) when preparing (mixing) your saltwater do it in large amounts so your salinity from water change to water change will stay more stable