I have recently “acquired” a 300 litre tank that had been previously set up for around a year. Due to the previous owners ill health I have taken it on. However after moving the tank to my home and rehousing the fish in a smaller tank, it has taken a week for me to set up the larger tank. The 3 filters were kept in bags and I haven’t cleaned them after reading that they can speed up the cycling.
1. Will the filters still be helpful for cycling the tank? Have they been out of water for too long?
On day 1 the reading were PH 6, ammonia 0.25, nitrite 0 and nitrate 0. I have added some API Quick Start to the tank upon recommendation but I am hesitant to put the fish in yet.
2. Has anyone used API Quick Start and is it safe for me to add fish now?
I am in no rush to add fish as I want to do it safely and not harm them. Just wanted some advice about the used filters as I have read that they can speed up the cycling.
Much of the beneficial bacteria will have either become dormant or died off, but there may still be some that will spring back to life once there is an ammonia source to feed on. I suggest getting a bottle of household ammonia to test how viable the bacteria is. Use the calculator in our guide to fishless cycling to dose to 3ppm then test 24 hours later for ammonia and nitrite. If either is present, you don't have enough bacteria and should continue as per a fishless cycle. https://www.fishkeeping.co.uk/articles ... hless-cycling-article.htm
However, what is being used to filter the smaller tank? If that is not a cycled filter the fish are at risk and you should test that one for ammonia and nitrite. If they are present, and the filter in that tank is not a cycled filter you would be better off putting the fish in the large tank with the previously cycled filter. This will give them a larger volume of water to dilute the toxins and the chance that the filter will build up enough bacteria quite quickly.
Thank you for the reply Fishlady. The small tank had been set up 2 weeks prior to putting the fish in but it was a new filter and at the time I wasn’t aware of cycling, I just knew I couldn’t put fish in a new tank straight away. This tank spiked at a reading of 8 for ammonia (nitrites and nitrates still reading 0) and I did a 50% water change. So I’m not sure if this has started cycling with the fish in.
Would it be beneficial to put some of the small tank filter media into the larger tank? The larger tank has gone to PH 7.2, ammonia 0, nitrite 0 and nitrate 5 although I had trouble distinguishing between the colours so it may be less than 5.
So from your reply I assume that I would be better putting the fish into the larger tank now. Is that correct?
The big tank won't show any ammonia until there's a source of ammonia in it. The small one with fish is at a very dangerous level of ammonia and you need to take action on that immediately.
As the small tank is not cycled and the larger tank may potentially still have some bacteria in the media your fish will be better off in the big tank. Even if it has no bacteria left, the larger water volume will mean toxins accumulate more slowly than in the smaller one.