Would I stress my fish if I...

[Mr31415]

... do a 40% water change every second day for say a week on my QT tank at SG 1.010? I have high nitrites (4mg/l) and although not dangerous to my fish, I'd like it lower until the Nitrospira colony has grown adequately.

[sir_dudeguy]

do you mean that you have high nitrates? i know that nitrates arent toxic to fish, but you put nitrites, and i'm not sure if those are or not.

[Mr31415]

Nitrites - and no, only at levels above say 40ppm they start to be dangerous to marine fish.

[Sk8r]

Take a look too at the Fluval, if I am correct and that is a cannister. In a system as you illustrate it, any filtration beyond live rock is superfluous and may become a problem.

[sir_dudeguy]

would it be the problem for nitrites tho? i know for a fact that canisters can cause nitrate problems, as it happened in mine, but i'm not sure on nitrites.

But i wouldnt recomend doing 40% water changes. And do you know why you have exess nitrites?

[davocean]

Actually you have it backwards as dudeguy stated.
Nitrates no big.
Nitrites, problems.
That's an extreme WC, but if your trites are high it would be the lesser of 2 evils.
This is your QT?
Why salinity so low?
Should be 1.025

[Mr31415]

Thanks - but I am actually asking something else. I am asking whether every other day 40% water changes in a QT will be bad for the fish? No filter that I add now will have any effect within the next week - so I want to keep the nitrites down by water changes until the bacteria colonise. This is a QT tank (not the one in my avatar) that does not have any LR in - just the sump with bioballs/ceramic noodles.

And no - I have no idea why they are high. The fish were fine for 2 weeks with 0 ammonia and < 0.05 nitrite. Suddenly the last wee it started climbing. No left over food, no dead animals...

[t5Nitro]

<a href=showthread.php?s=&postid=7983467#post7983467 target=_blank>Originally posted</a> by Sk8r
Take a look too at the Fluval, if I am correct and that is a cannister. In a system as you illustrate it, any filtration beyond live rock is superfluous and may become a problem.

Yes, correct that fluval filters are canister filters if you are still unsure.

[Mr31415]

Erm no I am not wrong. Nitrites are only dangerous to freshwater fish - not marine fish. Marine fish only start to show signs of stress above 40ppm. Read in the chemistry forums...

Salinity is low because I am doing hyposalinity treatment for Ich.

[AZDesertRat]

You need to seed the QT with bacteria from your main system to complete the nitrogen cycle and convert the nitrites to nitrates. I keep a Aqua Clear sponge in my sump all the time so when I set up my QT I hang the AquaClear 150 on the side and stick the sponge in it and I'm in business. Scrape some grunge out of your main sump and put it in the QT somewhere to jump start it.

[Mr31415]

Thanks AZDesertRat, but I have seeded the filter. I am however asking something else in this thread.

[davocean]

Nitrites might not be the only thing high.

[Mr31415]

Ammonia is 0, nitrate is low. pH is fine, temp is fine. SG is fine at 1.010.

[jmguerry12]

how old is the QT maybe its mid cycle??? how big is the QT? why dont you do 10% a day remember is you do water change you might take some of the good bacteria out too...just a thought

[sir_dudeguy]

ya if it hasnt cycled yet then that would be my guess. But 40% is just too much to do every other day imo...like jmguerry said...just do like a 10%...except i would only do it every other day instead of every day. Changing water very often isnt really that good i dont think.

[Mr31415]

QT is about 4 weeks running now, 2.5 weeks with fish. QT is in my signature - 120l.

[lux_06]

yeh i think this tank is still mid cycle and by seeding it and putting fish in after a week and a half u have just seen the end of the ammonia,

whateva u do is gonna stress the fish, and changing that much water is gonna be expensive and will mean you have to get your sg levels perfect every change, but new salt water would be so much better for the fish trying to get over ich then water with high nitrite... nitrite is a baaaaad thing for fish avoid it cos it wont be helping. and i guess thats what ur asking isnt it, your bio filter isnt working yet so can you keep the water fresh to get the nitrite levels down?

imo - yeh id either get the fish out or do mass waterchanges cos they wont survive ich and high trites. just try and do the water changes as calmly for the tank as possible.

adam

[Mr31415]

lux_06 - that is exactly what I am asking, yes. The Ich is gone for now - have not seen any visible parasites on them for 2 weeks. I'll do then 30% water changes at 1.009SG every other day - I can see my nitrates getting higher which is good - meaning the Nitrospira is growing...

[lux_06]

id abandon the idea of a biofilter working at all on this tank then so forget about trates cos you want to get readings of zero all the time if your gonna be changing that much water.

remember keep the ich treatment going for another 2 weeks minimum cos the parasite could just be in a differnt stage of its life cycle and still present in the water, just not on the fish.

if it were me takin this approach id do it with very dim light in the room so the fish didnt see me flashing about the tank heaps, take water out and put it back in as slowly as possible, just try and make the fish think its high and low tide hey!!!!

this is gonna take so much salt tho over the next 2 weeks mate! but it would proberly be cheaper then loosing ya fish!

[serpentman]

Here is an interesting article on the toxicity of nitrite. It is not nearly as toxic to marine fish as it is to freshwater.

http://reefkeeping.com/issues/2005-06/rhf/index.php

As far as the WC are concerned, I would make sure the water has been good and mixed for 24 hours for each WC as undissolved minerals could irritate them. Perhaps a 40% every other day might be sufficient.

[Amphiprion]

You can do large water changes. Just be sure all parameters are the same. I did the same thing when setting up a QT that never cycled or had any biofiltration (at the time).