I've just about reached the 6 week period and testing every 12 hrs at no ammonia or nitrites. Nitrates are high and this tells me I'm ready for the big water change I've been advised to do in the past. Only question I have is how much water I need to remove from the 10 gal tank? I fear that if I remove the recommended 90% it may disrupt things. I did not have a problem with this when I cycled my 29 gal, but just want to make sure since it's been awhile and it's a smaller tank. Thanks ahead with any advice!
Ending Fishless Cycle Water Change
- Thread starter wadcpo2
- Start date
Noahs ark6
Fish Herder
i would do a 70% water change
It's very. very unlikely that a water change would harm your cycle, and even if it did, it would only be a minor 'blip' and your filter would soon recover (as long as the new water is warm and dechlorinated, of course).
On the other hand, very high nirates can stall or stop a cycle, so I'd go ahead with the water change if I was you
On the other hand, very high nirates can stall or stop a cycle, so I'd go ahead with the water change if I was you
Thanks! I split the difference with a 60% water change, added 1ppm ammonia and tested within 1hr. after. Showed nitrites up a bit and ammonia as well. Retested after 12 hrs and everything fine with those. Nitrates still on higher side, but all my tanks that have been established after years also show the same nitrate levels and fish are doing fine so I think I'll be ok to start adding a few fish. PH maintaining same levels as all tanks as well.
Only question is how much ammonia do I need to keep putting in before I add the fish and how often?
Only question is how much ammonia do I need to keep putting in before I add the fish and how often?
waterdrop
Enthusiastic "Re-Beginner"
The point of the final "big" water change that serves as the gateway between fishless cycling and the introduction of the first stocking of fish is simply to lower the excess nitrate(NO3) level.
If by "disruption" you mean knocking over decorations or uprooting plants then those things can be fixed back up. If you are worried about disrupting the expression of the biological cycle, as fluttermoth as surmised, that is not an issue. Any substrate-clean-water-change carries the risk of creating blips in the ammonia and nitrite levels, but the maturity level that a qualifying week helps ensure means these should not be significant at the end of the fishless cycle or that the blips will still be taken care of within 12 hours or so.
If it is water level disruption, you could do a "2 step" change where you clean-siphon out to half or a little more, then refill, then immediately do it again. As you say, if the NO3 level you've achieved is similar to what your other fish have done ok in then you'll be fine, most species are pretty tolerant of NO3, dispite it being a negative. Followup water changes with the fish in can be done a little more frequently to help further lower it.
You can go either way with a last fishless cycle ammonia dose or two: you can just let the bacteria go without ammonia for a day, day and a half or so... or you can do a dose or two as long as you give them enough hours to completely deal with it and drop the tested level to zero ppm before the fish are added. Those last doses (and they can be smaller) won't add much nitrate.
(sorry for the length of that.. I think you've got the idea.. it's just that it seems a fair number of guest newcomers read these and it gives the opportunity to explain the thought.)
~~waterdrop~~
If by "disruption" you mean knocking over decorations or uprooting plants then those things can be fixed back up. If you are worried about disrupting the expression of the biological cycle, as fluttermoth as surmised, that is not an issue. Any substrate-clean-water-change carries the risk of creating blips in the ammonia and nitrite levels, but the maturity level that a qualifying week helps ensure means these should not be significant at the end of the fishless cycle or that the blips will still be taken care of within 12 hours or so.
If it is water level disruption, you could do a "2 step" change where you clean-siphon out to half or a little more, then refill, then immediately do it again. As you say, if the NO3 level you've achieved is similar to what your other fish have done ok in then you'll be fine, most species are pretty tolerant of NO3, dispite it being a negative. Followup water changes with the fish in can be done a little more frequently to help further lower it.
You can go either way with a last fishless cycle ammonia dose or two: you can just let the bacteria go without ammonia for a day, day and a half or so... or you can do a dose or two as long as you give them enough hours to completely deal with it and drop the tested level to zero ppm before the fish are added. Those last doses (and they can be smaller) won't add much nitrate.
(sorry for the length of that.. I think you've got the idea.. it's just that it seems a fair number of guest newcomers read these and it gives the opportunity to explain the thought.)
~~waterdrop~~
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