Tank recycling due to major water change. What to do?

[dav1d84]

A major water change (80%) was done, now the tank is cycling again (I see green and red slim growing). What do I do? It's been about a week since then. Do I do a small water change, like 10percent now? or do I let it finish cycling first?

 

[bertoni]

I'd let it be, unless you can measure ammonia. That large a water change is pretty hazardous, and I wouldn't want to add more stress. What are the water parameters?

 

[mikenpam]

Why did you perform the 80% water change? Also what size is your tank?

 

[Swanwillow]

red and green algae aren't bad... I have to agree, why did you do an 80% in the first place?

and what all is in the tank? fish? corals? etc?

 

[a4twenty]

what water did you use? you could have added nitrates and phosphates when you did the water change. and i have to agree with everyone else 80% is huge.

 

[tulkas71]

I have a question reguarding this.
If your LR and LS are providing the filtration, doesnt the water merely contain the byproducts for each stage of bacteria?

If a tank is fully cycled, meaning ammounts of ammonia, trites and trates are not measurable, should a water change of any magnitude have any effect let alone start a cycle over?

If it does, then it seems like theres some "good" bacteria living freely in the water. That would seem to imply theres not enough filtration going on with the rock and/or sand.
Or,
Maybe water changes this large remove the non measurable amounts amonia,trites and trates needed for the cycling, so there is a slight "die off" of this bacteria in your rock and sand causing them to replenish again causeing a "mini-cycle"?

Did I just answer my question? I am in the "new" forum after all

 

[reverendmaynard]

Well, I think the term cycling has been misused in this case. The poster doesn't mention ammonia, just algae. A properly done water change (match salinity, temp, ph, don't leave the LR exposed to air for more than a few minutes, etc) of even 100% should not affect the nitrogen cycle too much.

What can happen when you do a large water change is that some nutrients/minerals/metals that are normally kept at a pretty depleted level by the existing algae and/or other photosynthetic creatures gets a big boost, brought in by the new water. Normally this is associated with using tap water, or less than perfectly clean RO water, but it could even be the salt mix. This sudden influx of whatever it is that is limiting algae growth allows for an algae bloom.

 

[tulkas71]

Thanks!
Slowy but surely filling my knowledge gaps.
Sorry guys didnt intend to hijack post.

 

[Swanwillow]

I agree with the rev: but I have a suspicion that the water change was done for a reason, and want to know why: most people can't do 80% water changes: I did it on a 35 gallon hex for a few days, but only 50%... its HARD to move that amount of water!!!! even 5 gallon water changes on a ten gallon QT tank daily will take its toll quickly.

the reason we ask why is: the ammonia could have been high, or the nitrates, trites, things like that. was the an existing problem with the tank that encouraged a water change of that magnitude? etc etc.

My tank recently leaked, so I went ahead and replaced 95% of the water... no problems, except for the new diatom bloom but why would yuo say the tank is cycling if you only see algae? algae is normal, IMO

and asking questions isn't hijacking the thread: it encourages a debate over things... as long as its on the same subject!!!

 

[bertoni]

I wouldn't do a change over 25% except in cases of emergency. I would worry about shocking the organisms with a sudden change in parameters. Some people do get away with them. The chemistry forum has some discussions on this issue.

Also, exposing many sponges to air causes them to die, which can lead to a lot of rotting and release of toxins, so I tend to avoid exposing live rock during a water change.