Nitrate spike after water change?

[JodiW]

Kind of weird, huh?

Usually my nitrates are around 20, which is basically what's in my tap water that I use. (I know I need a RO/DI, but can't get one yet.) I did a 10 gallon WC in my 75 gal. tank yesterday afternoon and when I tested the water today, my nitrates are much higher. The nitrate test is extremely hard to read (shades of orange, I'm never sure I'm reading it right) but it seems that they are between 40-80 now. It's possible they've always been that high and I was just reading it wrong before, but that's how it looks to me on this particular day.

Everything else is where it should be (pH, amm, nitrites, etc.). Oh, and I got a phosphate test kit today out of curiosity since I have so much green algae. The phosphates are testing at 1 (comes from the tap at .5).

The only thing I did different yesterday was rinsing out the filter media from the top of my wet/dry. The blue & white one that lays on top of the bio ball chamber. I'd never done anything with it since setting up the tank and oh boy, was it ever nasty! I rinsed it out in the dirty WC water, wrung it out gently and replaced it. Could this have caused a spike by somehow releasing yucky stuff it had previously trapped? If so, how do I deal with it in the future?

Any help greatly appreciated!

Jodi W

 

[arminkropp]

You probably did upset the biofilter a little by cleaning it. Make a regular habit of cleaning it and not waiting so long. One question, do you still use the bio balls?
again they harbor nitrate alot. As far as water goes see if you can spare a couple bucks and do your water changes with RO or RO/DI water from the local water shop. should be only a couple bucks for every waterchange. Its well worth the effort.

 

[lando]

I agree, you probablly disrupted the biological filtration a bit. It should settle down. Adding some LR to your tank would certainly help your NO3 levels (as would a skimmer). But all in good time. Also, you may want to get a second test kit of a different type to verify your high readings. You can also have the LFS do this as well. On a side note, where are your at in Iowa. I grew up in Sheldon (northwest corner of the state) and went to ISU (go Cyclones.)