60 L To 200 L Tank Change

The UK allows up to 0.5 ppm ammonia in tap water. One source of this ammonia is the use of chloramine as a disinfectant instead of chlorine.

Prime is only one of a range of dechlorinators that 'detoxifies' ammonia. Most of them do this. But Prime is the only one that claims to 'detoxify' nitrite as well, though the company admits they don't know how it does that, they only found out it did after people reported it.
As long as it's only ammonia in the water, any dechlorinator that 'detoxifies' ammonia will do. They do this because the use of chloramine in other countries is widespread, and some companies in the UK also use it. Chloramine is a chlorine and an ammonia joined together. The chlorine removing ingredient splits them apart and removes the chlorine leaving the ammonia part in the tank water. The tank bacteria will eat it within a few hours but the ammonia detoxifier renders this ammonia less harmful until it has all been eaten.
Our test kits will detect the ammonia in the water plus the detoxified ammonia so even after using an ammonia detoxifying dechlorinator ammonia will still show up in the test.
One thing to bear in mind is that the detoxifying process lasts only about 24 hours so water changes still need to be done if the ammonia reading is above the safe limit next day, but the fish are safer between water changes.

In your situation, I would suggest using any one of the dechlorinators that detoxify ammonia since you have some in your tap water. But the choice of which one is a personal thing. I know a lot of people like Prime because it does detoxify ammonia and is concentrated so you only use a bit meaning it works out cheaper overall, but a number of other people won't use it because Seachem won't say what is in it. They say the ingredients are a trade secret.


Now that you have set up the external it is just a question of waiting until both ammonia and nitrite stay at zero. Once you are sure they are stable, you can even think about adding more fish. A few at a time, waiting till you've had a week of double zeros between batches of new fish. As a rough guide, it is safe to add in one batch one third of the fish already in the tank.

@fruitbat I thinks its fairly normal to have the intake at the bottom, that's where I put mine, the return is then diagonally opposite at the top to create a good mixed flow across the tank. You are correct if the filter springs a leak it will drain the tank unless you have a skimmer on the intake line but that is the nature of the beast.
Just take care that the filter connections are not stressed by the pipe and check for leaks after an maintenance. You could drill a 5mm hole in the intake pipe 20mm under the water surface to act as a syphon break but even 20mm of water leaking will look a bit like a disaster when you discover it, so leak free is the preferred solution

hi, 2 weeks in and things seem ok , my ammonia is still at .5 to 1 and ph 6.6 which it has dropped from 7.6, the ammonia calc you gave me shows they are ok though i do water changes,still no nitrites yet.. i also got an algae bloom :-( . i put some live plants in last week but they starting to wilt already but as i said the fish and our 6 fry seem to be ok. is there anything i can do to get the ammonia down or is it a wait and see and keep doing water changes and is there any way of getting rid of algie bloom, thanks for any advice sue ....again :-) 

Fruitbat, did you have problems with very soft water a while ago? Or am I confusing you with someone else?

If it was you with very soft water, that could account for the pH drop as all sorts of things excreted by fish can be acidic. Maybe try putting some crushed coral in a bag in the filter to help keep the pH level.

If you can squeeze it in the filter it will get more water flow over it so it will dissolve better.

At low pH the filter bacteria stop multiplying, and this could be what you are seeing with you ammonia reading. The good news is that the more acidic, the more of the ammonia there is in the less toxic form.

With your pH, that ammonia reading is fine. Free ammonia is very low at at low pH and yours will be well under the 0.02 critical level for free ammonia.

So as your ammonia is nice and low, and nitrite at zero, and they have been for over a week, yes you can get more fish 

The maximum you should get at each purchase is a third of the number of fish already in the tank, and check the levels for a few days after putting them in.

hooray to me and thanks to you guys for your advice, ill be out tomorrow to buy a few fishys :-)    just a note if you remember my first batch of fry a while back,well they have had babies of their own and they are doing fine too.. :-) love this hobby and my wife and i love sitting down and watching them  .. cheers guys

hi guys, just an update if anyone interested.. my tank is now thriving and we have 14 babies at the moment, sunset platys and mollies and now have a baby yellow rabbit snail we call albert. i have 46 fish inc babies and 6 rabbit snails and 3 shrimps.. fish are mollies,platys(sunset and panda),rummys, cardinals,black tail sword fish and 3 sailfish mollies.. they all seem to get on at the moment and the best thing is my wife now loves fish keeping too,we often sit down for half an hour watching them .. again many thanks for your advice ..  cheers

Excellent news @fruitbat and well done! I went through the something similar recently and being in a position to watch eggs and babies develope is completely fascinating so I know the feeling. Keep up the good work

hi guys, we now have issac our second little yellow rabbit snail baby, everything fine , we do lose the odd fish now and again but overall very happy with upgrading to bigger tank... worst thing is we have too many babies and have to pick which have to go back to the shop !