[Innes]

Would I have to re-cycle my tank if I rince the gravel, and do a water change?
I have to reduce the nitrates, and I have already changes 75% of the water twice and also a 50% water change.
I still have a nitrate problem, however everything else is great!

 

[Judazzz]

I guess rincing your gravel with warm (not hot!!!) water won't kill all bacteria, so you don't have to completely recycle your tank, especially when you don't change your filter media (I don't know what kind of filter you are using...) Water changes shouldn't affect the cycle in any way, since the bacteria are located in the substrate and filter, not in the water (I'm not 100% positive about this one, though).
I'd just set-up your tank, leave it running for two or three days, drop in some expendable fish (goldfish or guppies or whatever fish you hate :laugh: ), and see what happens. If it's all cool after a week, you could start populating your tank with normal (ie. cool) fish again.

I had a somewhat similar situation a short while ago: I have moved to a new house about a month ago, and I replaced more than half the gravel in the process. I kept about 40% of the old gravel, with the new gravel on top of that. Besides that, I kept about 25% of the 'old' water: the rest came straight from the tap ('treated' with Aquaclear). I didn't replace the filter media, and used plants, rock and wood from the old setup. None of my fish died because of all this... Fish are more hardy than many people think.

 

[Grosse Gurke]

Innes,
If you are having a nitrate problem after you did a 75% water change you should check you tap water and see if it has nitrates. I dont think rinsing your gravel will have any affect on nitrates. The only way I know to reduce nitrates is water changes and plants.

 

[Innes]

I have checked the tap water, it is good, not quite perfect, but it is better than my tanks, In the tank I had the disaster in the other day I had readings of 100+ nitrates, since then I have done 2x75% water changes and a 50% water change & cleaned just over half of the gravel (it was really dirty!) and my newest results show -orange- around 12.5.
I am now much more worried about my other tanks, they both show high nitrates, and I have also done water changes in these tanks over the past few days.
I want to clean the gravel because I can see it is filthy, and I have undergravel filtration (2xhagen 201) so I guess the bit at the bottom is clogged up with dirt.
the problem is I can't afford to cycle the tanks, they have fish in them.
But I also need to get them sorted, is it worth getting it done and seeing how things turn out? - the fish are not excactly in the best situation at the moment anyway so wouldn't it be a good idea to just empty, clean and restart?
which is best for the fish?

 

[Grosse Gurke]

12.5 is not bad.
If it were me, I would remove most of the gravel, not wash it, just swish it around a bit in aquarium water, remove the UGF and toss it. Do a gravel vac to get as much of the crap out as possible. Then put back in the gravel. I dont believe this will have much effect on the cycle.
This is just what I would do, Im not sure what would be the recommended action from someone with more experience.

 

[WebHostExpert]

You need bio filters on your tank, it has to have a natural cycle, somewhere theres a weak link that is causing a backup of nitrates.

 

[Innes]

can you explain this so I would understand it?

 

[Grosse Gurke]

You need bio filters on your tank, it has to have a natural cycle, somewhere theres a weak link that is causing a backup of nitrates.

I am not sure what you mean by this. My understanding is that nitrates are the end result of the cycle and are removed by water changes. If you had amonia or nitrites I could see a problem in your filtration such as not enough bio filtration, but not nitrates.

 

[nitrofish]

I do 20% water changes thice a week and I still have trace amounts of nitrate also.

rinceing gravel wont hurt it unless the tempature is too hot or the water has chlorine in it or if you scrub the gravel.

plants don't remove enough nitrates to make it worth your wile ,just got to keep doing the water changes,(posibly larger changes are nessary) theres realy no way around it.don't try to get nitrates down to zero, thats prety difacult, just make sure its in the safe levels. just remember nitrate is the least toxic of all compaired to ammonia and nitrite, so don't panic.

 

[Innes]

I kinda want to have clean tanks for once anyway, so I am going to take the opportunity to clean them out.
as for new filters - you got to be joking, right?
There is nothing wrong with undergravel filters, in fact they are quite good!

I also sussed that my test kits are out of date so that might help to explain some things

 

[Grosse Gurke]

If you uncycle your tanks Innes, you are going to cycle your tanks with fish arnt you

 

[Innes]

I will try not to un-cycle my tanks

 

[Innes]

Well I have cleaned out the tanks now - lets see if the fish survive!

 

[Xenon]

moved to equipment questions.