Wierd tank cycle

[sharn]

A lady came in the other day to get her water tested for a tank that is kept at a daycare (she maintains it). Apparently the tank was stocked until about a month ago when the fish died (suspected ammonia poisioning or similar). She knows not to clean the filter media in water and what not and has been doing w/c's twice weekly since the fish died and hasnt added anything to keep the bacteria going (fish food etc) except 'cycle'.

The readings were:

Ammonia: 4ppm

Nitrite: .25ppm

Nitrate: 5ppm

I found it wierd that she was still getting a considerable ammonia reading when she isnt feeding the tank and is doing large w/c's? I suggested that she stop the w/c's and feed the tank very lightly to keep bacteria going and see if that levels things back out as her w/c's would just be prolonging the cycle right?

Any advice would be appreciated as the daycare is getting a bit sick of having a tank with no fish :lol:

[Ianab]

There must be an ongoing source for the ammonia.

Still something hidden and decomposing in the tank?

Large dead fish and/or old food under a log or something like that.

I would suggest they empty the tank, wash out the gravel etc. Keep the cycled filter intact in a bucket of water. Then refill with the now clean gravel, rocks and fresh water. Use the established filter and the cycle to re-establish the tank.

Hopefully then the water will be OK for a couple of fish in a few days time and carefully build up the stock again.

I'm thinking that in a daycare centre you cant really be sure whats been dropped into the tank. :-? But I suspect something must have been.

Cheers

Ian

[mr pleco]

if the filter is cycled why would you need cycle to reestablish the tank?

just put that filter back on to the new tank after cleaned and run it for a couple of days and test the water ...

agree something is more likely poisoning the fish and the water

whats the ph of the tank is there a dead fish in the filter somewhere

dosent cycle add ammonia anyway ?

[Adrienne]

A thought :roll: the children can't get their hands into the tank can they. I was sort of thinking - play dough etc etc. Or something the cleaners are using.

My husband used to have one of my tanks in his science class until the fish started dying. I worked out that the children had been putting their icky hands in the tank with all sorts of stuff on them. To cap it off one day I went in and there was a cork that had been used in a chemical bottle bobbing in the tank and all the fish were dead.

[sharn]

i asked her if it was possible the kids can get to it but apparently not. i also asked if she had any decorations and if she had checked them and she said she had so who knows.

if her water isnt settling down with her not playing with it so much i will suggest the tank break down and leaving the filter as is.

thanks guys

[Caryl]

With no fish in the tank the bacteria will be dying and that would be the source of the ammonia?

[Ira]

I kinda doubt that... Bacteria starve to death from no ammonia. Their dying creates ammonia, surviving bacteria eat it. Bacteria don't die, ammonia=0.

[smidey]

my sister works in a daycare in queenstown, they had losses when some playdough was posted in there. that is normal she said & they dont normally die. she discovered that the particular dough this day had spices like lavender in it. they still leave it in easy reach of children so they can interact with them ...... pc bullsh..