High Nitrate After Clean

[jeex87]

Hi All,

I appreciate all the advice in advance. Thank you!

I have a 300L tropical tank, I did a standard water test before doing a water change. Nothing was super strange, fairly standard. Nitrate levels were sitting about 10ppm. It was time for a water change anyhow.

The one thing I did different this time though was, before I did a water change I scrubbed with a rough scrubber the algae which had started to accumulate on the side and back glass of the tank. No chemicals or anything, just the scrubber (This scrubber is only used for the tank - never used for anything else). Once done I did a 35-40% water change.

I've let the tank settle for 2 hours then came back and tested the water as I always do. That's when I got the shock of 160+ppm Nitrate levels! Everything else is fine. I tested 3 times to ensure I didn't do the test wrong etc. Same result.

I then tested the water from the tap, no Nitrate. I tested the water from the hose which the water came from, no Nitrate.

Could this huge spike be cause from the scrubbing of the algae off the glass in the tank?

What should I do? I've already done a fairly large water change, should I do another?

 

[King Fisher]

A lot of dead algae can raise nitrates in the tank but generally algae feeds off nitrates. Has it been awhile since you cleaned your filters or vacuumed your substrate?

 

[jeex87]

Hi King Fisher,

I cleaned the canister filter about 2.5 months ago.
Last water change would have been about 3 weeks ago. I test the water every 5 days then perform a water change when noticing changes or if nothing changes I do a change every 3 weeks, so I don't have stale water.

 

[King Fisher]

I'd clean the filter and the substrate. Run it for 24 hours then test the water.

 

[jeex87]

Will do.
Do you think the fish be okay for 24 hours with such a high level?

 

[King Fisher]

Ya they'll be ok. It's the prolonged exposure that will hurt them.

 

[jeex87]

I've cleaned the filter and substrate - its been a little over 24 hours. Didn't change.

Every 8-10 hours since I've been changing 20% of the water, its slowly going down.

 

[King Fisher]

Strange. Are you shaking the hell out of the nitrate test bottles before you use them. I mean literally banging them against something or your palm? API is notorious for showing high nitrate readings if the bottles aren't shaked enough.

 

[jeex87]

Hi King Fisher,

Sure am! I forgot to mention I did that

I also tried a testing strip I had lying around.

When I get home tonight I'm going to retest and see how it is.