i clean my tank once a week and do a 10 percent water change. my tank has been running for up to 2 months. and my nitrates are at 20ppm. i normally just rinse out the media in the filter. but i guess i have to wash out the entire filter. but anyhow i am going to get some ocean water tomorrow so hopefully i could correct some issues concerning my water.
Be sure to check the salinity if you go with ocean water. It's pretty uncommon to do that but I'm sure I've read at least one thread in the past of someone having tried. In your best case scenario it won't address your nitrate issue though because wherever the water comes from, it shouldn't have nitrates present.
Ok - so 5 fish in a 25g tank that is 2 months old - that's your problem in a nutshell. Given that most tanks take a month or more to cycle (longer if it's not all LR), that means you either added fish to a tank that wasn't cycled, or you added 5 fish in the space of one month - either way it's a severe case of rushing that your bacteria could never hope to keep up with. Now, how to fix it?
(if you're wondering, your tank should be between 4 and 8 months old before it has that many fish. 4-8 weeks between fish (hopefully to QT), and allowing for a month of cycling but assuming your clowns and damsels were added as pairs)
You mentioned doing a 10% water change weekly - so the most you would hope to be removing from the tank on a weekly basis is 2ppm. That means your tank only has to produce 2ppm weekly to keep you at your 20ppm mark - that's pretty easy given how many fish you have. Add to that the fact that your tank is only 2 months old and I'd say you are very lucky to be doing so well.
Except, re-reading your original post I see you mention that your ammonia is fluctuating (I originally thought you meant pH, which would be normal). This is a very bad thing as it's toxic to everything in the tank. I suggest getting an ammonia badge (cheap) and stick it in the tank so you can keep an eye on it. If you see ammonia - do a water change immediately. And that's going to be your long term solution as well.
Try is moving to a 20% weekly water change - you can definitely expect to be changing more than the baseline norm when you have a lot of fish in a small space. You could consider 30% if necessary. You definitely do not want to add anything to that tank for several months.
Regarding the filter, you mentioned rinsing the media. There are probably two types of filters at work here - one with carbon and one that houses your beneficial bacteria (ex. bio-wheel or ceramic discs, plugs etc). Normally you could toss the later since you have live rock - but your tank is so new and crowded that I'd suggest that if you have it, keep it for now - and if you rinse it - do it in salt water. You can't afford to kill off the good bacteria right now. If you are rinsing your carbon filters - stop - just toss them and replace them until you see your numbers coming down - then you can potentially work your way back to a cheaper schedule.
So yea, we say it all the time, rushing is bad. But it's already done so just focus on being aggressive about your filtration and upping the volume of your water changes. And keep a close eye on feeding of course.
By the way - you didn't say - have you been treating your tap water?
And post pics! We never get enough pics :sad1:
**edit** doh - sandwi beat me to the WC punch while I as writing my novel - sorry sandwi
