Hi all, I have just purchased a 90l tank from eBay. To home my black moor currently in a 15l tank.

Question is, should I sterilise the new tank before the swap. Also what's the best way to set it up and swap it over?

Hi joe

I'm sure the BM will be far happier in a bigger tank for now. Bear in mind though that that tank will only be for growing on, and given he would do well with a friend, you will be looking at upgrading again some time soon.

Linky here: http://www.fishkeeping.co.uk/articles ... -size-life-expectancy.htm

Yes, the tank will need a clean. Lemon juice and bicarb of soda will assist (the bicarb can be mixed into a paste for any stubborn limescale residue). Then rinse, rinse, rinse.

You can then do what's called an 'immediate cycle'

True, whilst all surfaces in the existing tank are coated with some bacteria the vast majority are housed in the filter. Moving over existing gravel might help a bit, but it's not vital if you want to change the colour scheme/decor at this stage. The most crucial thing though is the filter media.

Add new/pre rinsed substrate to new tank. Fill up the new tank with temp similar water (test the tank for 24 hours before though first, so you know it doesn't leak), add water treatment to deal with chlorine/chloramine.

Move the existing filter over to run alongside the new one, or simply add all the media to the new filter - cram it in, it doesn't have to look pretty and if it's sponge it should squidge in.

If you plan to run the filters alongside each other, the old one needs to run for about 6-8 weeks to ensure the water stays safe whilst the new media grows the bacteria colony.

Add the filters and switch on, then add the fish, acclimatising them first in bags as you would if they were new additions. I'd suggest leaving the BM in the 15 litre tank whilst you move the existing filter media over, taking just his water over with him in the bag.

You can then move any existing plants/add new plants, twiddle and fuss with layout as the last stage as you won't be clock watching at this point.

Hey presto, same amount of bacteria but more water volume. When upgrading like this you don't need to wait for the new bigger tank to cycle. Testing each day for a week or so is recommended so you can catch and deal with any possible small spikes that may occur in the water parameters

Note: Normally, FK would suggest saving as much old tank water as possible and moving this at the same time to add to the new tank water, but in this instance I don't think this is a wise move. Given the existing water is likely to be quite poor, not sure it would do the fish any favours

Many thanks for the detailed reply.

I think my gf was planning on cleaning it out with Milton steriliser, will this help?

Milton liquid would be fine too (won't get rid of any limescale desposits though) but make sure you rinse uber well