Filters and bacteria. Water change or not?

Right, I have upgrade my filter from an internal fluval 2 plus to an external fluval 105. Tank already has fish in it and the tank has been going for about a month. It is a 90litre tank with 9 separate live plants... (not sure if that matters).





I took out my old filter and installed the new one (it was not a simple click on plug in set up, needed to to a little DIY on my tank for tubing and stuff but it is in place now and working well). I read somewhere that I should run both new and old filters at the same time for a few weeks then take the old one out completely. I came on here to ask if this was the case... but was told that because the old filter was out of the water for a day, all the benifical bacteria would be dead. Been 3 days since and fish/plants/water seem good. I still have not put the old one back in based on the answer that I got.





So my question is,:-





How long will it take for the filter to build up bacteria?


How long/fast does bacteria grow?

Filters and bacteria. Water change or not?
water change
Reply:no water change.


because most Bactria will not leave with water.


so you have to use some type of object or cleanser to prevent Bactria.
Reply:If you took the old filter out for a day chances are the bacteria had died. There will be some bacteria in the tank itself living on/in the gravel and rocks and plants as well as the water itself.





After a month your tank probably wasn't completely cycled yet anyway so I would just carry on with the new filter now and keep doing water tests until everything is right for your fish.





Doing a fishless cycle would have been the best idea but it's too late for that now. Only do water changes if your levels of ammonia and nitrites are too high. 10% weekly is enough for an established tank.





**
Reply:The bulk of the bacteria grows on the filter pad. It's all about surface area. The bacteria grows everywhere, but the pad is made to have an enormous surface area packed into a small space.





Taking the old filter out does NOT 'kill' the bacteria in the tank. You will be fine, as long as you don't make any other sudden changes in the tank for at least a couple weeks. Give the tank time to adjust. Don't add new fish or change the rock.





More detail on bacteria: The 'cycle' uses two different species of bacteria to convert the toxins in the water to less harmful organic material. When your fish excrete waste, certain bacteria feed on the ammonia in it. The by-product of this 'dinner' is nitrate. Nitrates are poisonous when they build up in the water, but not nearly as bad as ammonia. That's why you still have to do water changes every so often.





I have found that a 'slow but steady' approach works great on aquariums. For the first 2 months, I keep only one, hardy fish in a tank. When the cycle is ready, I add one or two fish per week until the tank is populated. I rarely lose a new fish.





Good luck.





http://freshaquarium.about.com/cs/biolog...
Reply:Dear friend





Well as far bacteria is concerned they are ubicutous, so it hardly matters that u have changed filter so useful bacteria are lost.


Anyways to set up a tank it requires approximately 1-2 week to get stablised. So even few hours is enough to get useful bacteria which can change nitrites into nitrates.


Filter is of varoius types, usually filter with bio balls have great tendency to develop microrganisms, which can further controle ammonia level in ur tank
Reply:Hi Darren, because you took your old filter out for a day the colony of good bugs in it will certainly have died if it was allowed to dry out so you may as well not bother using it at all. You need to be keeping a very close eye on your parameters-daily would be good %26amp; be prepared to do large [around 50%] partial water changes every couple of days [or as necessary] to keep potentially fatal ammonia %26amp; nitrite in check-as near to zero as you can. Don't worry, despite what many people believe the good bugs grow %26amp; live in your filter, plants, decorations %26amp; gravel NOT in the water so you will net be interfering with the growing colony doing these changes.





What I would advise caution in for a couple for weeks is vacuuming your gravel too thoroughly-let a little loose debris accumulate-not so much as to swing your ammonia %26amp; nitrite to dangerous levels or cloud your tank but enough to hasten the growth of the good bugs-typically around 6 to 8 weeks. Personally I don't use anything that is claimed to work miracles such as StressZyme although each to their own-I find the best solution to a healthy tank is as little chemical input as possible. I think as you transferred some of your old décor you will have brought some of the good bugs from your old tank %26amp; these will help 'seed' your new tank %26amp; may well keep any dangerous toxic spike down but keep a close eye on proceedings %26amp; please feel free email me if I can help further.
Reply:First off, taking out the old filter riight away was a bad move, but you know that now, and it's too late to go back.





There are some bacteria living on every surface in the tank, so you still have a small amount of biofilter in the tank.





What you need to do now is closely monitor the water and do water changes as needed to keep the ammonia and nitrite down below 1ppm untill the new filter starts working. The filter will actually cycle faster if you let the levels rise, but your fish will probably die in the meantime. Doing water changes means the cycle is going to take longer, but your fish will survive it.





Also cut back on the feeding for a while, less food means less ammonia and less stress on your fish.





If the tank is only lightly stocked the ammonia may not even rise to dangerous levels, or you may need to do 50% changes per day, depends on your tank and fish.





Whatever happens, water changes are your friend in this situation.





Ian