Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: Pelajuch on March 18, 2015, 07:37:20 PM

Title: Safe levels
Post by: Pelajuch on March 18, 2015, 07:37:20 PM
Hello all, new here, signed up a couple of weeks ago and have been reading all the posts. I am approaching (hopefully) the end of a fishless cycle in my first ever tank which is 110 litres capacity. I have some questions as follows.
1. How much should the "big water change" once the cycle is complete be?
2. I hope to refill after the water removal straight from the tap. Can I add the required amount of dechlorinator to the tank before refilling or straight after or will either of these affect the bacteria I have so lovingly grown?
3. How much and how often should water changes be once I have fish in?
4. How often should I test once the fish are in and what are safe levels of Ammonia, Nitrite and Nitrate in a stocked tank?

I'm sure I'll think of more, but thats plenty for now..

Cheers
Title: Re: Safe levels
Post by: Sue on March 18, 2015, 07:54:39 PM
Hi and welcome  :wave:

And well done on the fishless cycle  ;D


1. I would drain the tank to the substrate, or if that sounds too much trouble, at least 75%. You want to add fish when there is just the amount of nitrate in your tapwater and the cycling process will have been making nitrate you need to get rid of.

2. I will assume you have an internal filter on that sized tank, which you will turn off during a water change as it doesn't do the motor any good to run it out of water. Add a small amount of water then add dechlorinator. When you add the rest of the water it will swirl around mixing the dechlorinator in. Newly grown bacteria colonies haven't had time to fully embed into the newly grown biofilm so you do need to be careful of them. Once the tank has been running a good few months, the biofilm will protect the bacteria quite well even from any chlorine/chloramine that gets to them before you add dechlorinator.
And on the subject of turning things off before starting a water change, don't forget the heater too. Many will shatter if they switch on out of water.

3. This depends on how many fish you have, how messy they are (ie how much they poo) and whether you have live plants.
For a reasonably stocked tank with no live plants, start at 25% a week, cleaning the substrate at the same time. if you have gravel, this means pushing the siphon tube into the gravel to get the muck out of there.
For a lightly stocked tank with a lot of plants, you can drop down to 10%.

Let the nitrate level guide you once the tank is fully stocked. Measure your tap water nitrate and do water changes as big and as often as needed to stop it reaching 20 higher than the tap level. Start at 25% a week and test before the next water change. If you find it hasn't gone up much, do less than 25%.

4. Test for several days every time you add fish or do anything to the tank eg washing filter media or removing decor. And test if the fish start to behave oddly. Once you've had the tank several months, test when you remember or add new fish.
In a stocked tank, ammonia and nitrite should be zero. Nitrate should be less than 20 above the level in your tap water.
Title: Re: Safe levels
Post by: Pelajuch on March 19, 2015, 10:17:18 PM
Thanks for the detailed answer Sue.  :). So much to learn! It might be worth adding the water change/ dechlorinator info at the end of your fishless cycling post to help other newbies.  Thanks again.
Title: Re: Safe levels
Post by: Sue on March 20, 2015, 12:14:23 PM
I'll see if it will let me. Last time I tried to modify that post, it wouldn't let me as it was too long! Though I think the new owner has relaxed the post length restrictions.