accidentally left filter off for 12 hours!

[Aquaristair]

Carelessly, I forgot to re-start the filter after feeding our fish last night and only noticed it this morning about 12 hours later when I came to feed them!
Filter is external canister 13L (3.4 US gal) with 10x water change per hour. Aquamanta EFX 400.
Water temp dropped from 24.5 to 22C. NH3 = 0 (indistinguishable from tap water); NO2 ~ 0.25 (API test).
NH3 & NO2 have been 0 (and never any NO2) since after first cycle. pH is ~7.5, KH 5.5
Tank is 150L (~40 US gal). We will change 50% water and add filter start bacteria following visit to LFS this pm.
Fish: 5 Pentazona barbs, 6 three line cory, 10 glowlight danio, 11 neon tetra, 5 firehead (aka rummy nose) tetra, 2 clown pleco, 2 marbled hatchet fish.
Well planted with gravel substrate
All fish are small as tank stocked recently.
I understand (info on power cuts from LFS) that filter bacteria will die after about 1 hour...
Any advice for immediate care and follow up welcome please.
Many thanks,
Aquaristair

 

[meegosh]

I honestly think you'll be fine. I don't know an exact number but 1 hour sounds way too short. Last winter we lost power for 3 days and when I restarted everything I didn't have any spikes or anything. I ran a heater and an airstone, that was it.

 

[rasbora]

thank you for posting this. I just realized that I also forgot to turn on my filter after doing maintenance about one hour ago.

 

[NYgiantsRP]

I also lost power for 2 days, NOTHING ran for almost 1 1/2 days until I got a generator. I had a little spike in nitrites but noting major, I just did a water change the next day to kind of refresh it.

 

[rreekers]

you should be totally fine, it happens. i do it too, about once a month at least between my 3 tanks... my main tank 60g, i left my filter off for 17 hours last week and only noticed because the water looked a little different. started it up and the cloudy tint went away within 25 mins. my parameters had no fluctuation. but i also had air stones going so there was water circulation/movement

do you have air stones? they are lifesavers and are a great temporary backup

 

[jcolon]

Carelessly, I forgot to re-start the filter after feeding our fish last night and only noticed it this morning about 12 hours later when I came to feed them!
Filter is external canister 13L (3.4 US gal) with 10x water change per hour. Aquamanta EFX 400.
Water temp dropped from 24.5 to 22C. NH3 = 0 (indistinguishable from tap water); NO2 ~ 0.25 (API test).
NH3 & NO2 have been 0 (and never any NO2) since after first cycle. pH is ~7.5, KH 5.5
Tank is 150L (~40 US gal). We will change 50% water and add filter start bacteria following visit to LFS this pm.
Fish: 5 Pentazona barbs, 6 three line cory, 10 glowlight danio, 11 neon tetra, 5 firehead (aka rummy nose) tetra, 2 clown pleco, 2 marbled hatchet fish.
Well planted with gravel substrate
All fish are small as tank stocked recently.
I understand (info on power cuts from LFS) that filter bacteria will die after about 1 hour...
Any advice for immediate care and follow up welcome please.
Many thanks,
Aquaristair

I'd say your fine, as long as the filter media in the canister remained wet, there should've been enough for the bacteria to stay alive. Just start it up and monitor your parameters. I'd doubt you lost any bacteria.