OK update :

Ammonia has now gone to zero.
All others same as above .... on the right track so.

As for what happened ?
My 'change' water stands overnight in a large bin with the spare heater in it. Stress Coat is then added to the tank (not the bin)once the change has been made. Think I know what you are going to say.
I understood the Stress Coat would sort out the Chlorine.

Not confident I can rule overfeeding out. Must dicipline myself to one pinch(2 minutes of feeding) every 2nd day...would you agree ?

All fish are accounted for (dead or alive)each day so no decaying bodies.

Only have plastic plants.

I did however find an algae wafer stuck under the filter and this could have been there for a couple of weeks or so but would this be a contributor ?

Heading for Aquatic Village today for the external filter .

Can you get Stress Coat for the aquarist there ???

Ever patient....ya right.
Processor.

Ammonia 0 - good. Now lets wait for the Nitrites. They may take a little longer to do down to 0 as the bacteria here multiply slower.

MOST IMPORTANT :!: - You guessed it ...... You must add the stress coat to the bin prior to adding the water to the tank. If you add the water to the tank and then add the stress coat you are adding water with Chlorine in it to the tank and it can kill the bacteria and fish, even if the time between adding the water and then adding the stress coat to the tank is small you are causing a problem.

When cleaning filters etc, use water from the tank to do so (when doing a water change use the water you have taken out). If you don't then you risk killing the bacteria in the filters etc.

Rule of thumb - under no circumstance should water which has not had the chlorine remove be allowed near the tank or equipment.

Feeding - I feed daily myself but you do need discipline to ensure that all food is eaten. Uneaten food after a few minutes should be removed.

Algae wafer may have been a contributor but probably not the main cause.

You can get everything you need in aquatic village.

Monty

External filter from Aquatic village (cool place) fitted and running as of 10 mins ago.
Looking forward to getting nice fishys in a couple of weeks.

This lark is dead easy don't you think ???

Many many thanks Monty I was despairing to say the least.

Yours etc.,
Enthusiastic Processor.

I'm delighted to see you call yourself 'Enthusiastic Processor', at least your difficulties have not gotton you down.

You will find a huge difference with the external too.I never looked back. It will take some time to build up bacteria etc. I wouldn't even bother thinking about cleaning it for a number of weeks at least.

At the moment just keep checking the water for ammonia and nitrite until you get these down to 0. (Continue to monitor the ammonia - just in case ) Your water changes will help stop these from getting too high. Remember, mix the stress coat with the water in the bin, prior to putting into the tank.

All going well soon you can drop down to a weekly water change of 20-25%. In fact the water changes in a cycled tank are to control the nitrate levels - although they do give us the opportunity to clean the substrate of any nasty 'crap' that has built up

Please let us know how you get on over the coming week or 2

Monty

Ammonia zero
Nitrite zero
Fish happy
Processor very happy.
Many thanks.

I'm delighted for you. I'd leave it a couple of weeks before putting any more fish in and now start keeping an eye on the nitrates. Good idea to check the nitrates in your tap water for comparision to the tank so you can see how much they are going up so you can get a better idea of the amount of water you need to change.

Best of luck

Monty