Hi

We have had Eric the lobster since Monday. I have been checking the nitrite levels every day. Day one the test was slighly pink so left it, day 2 it was pinker still so did a 25% water change and added some filter start. Today I have just done another test and the sample has come out very very dark pink which according to the instructions means that the bacteria in the filter is not yet established.
Im a bit worried I have done something wrong when cycling the tank.... should I do another water change today and add more filter start??

I would do 25% water changes every day and use one of these untill the nitrite drops to zero and stays at zero without the water changes Polyfilter Standard for Aquariums | Pets at Home

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Brilliant thanks!!

How did you cycle the tank? Do you know what sort of ammonia level it is cycled to handle? You should test the ammonia and pH levels too as they are important figures and will let you know how far in the cycling process you are. And your nitrate. In the meantime keep up with lots of daily water changes to keep toxicity down.

I cycled the tank by using some filter media from a friend's established tank. I then let the tank run for a further 4 days and checked the ph and nitrite. Nitrite was 0 and ph was 7.0. Im thinking maybe I did not cycle the tank long enough. Person at the fish shop said it would be fine but at the end of the day they just want to make a sale dont they.

I have been doing 25% water change everyday and adding filter start. Nitrite test today is still very pink. I have also removed some of the poop from the bottom.

Can I just check that I'm not overfeeding Eric. I normally give him a couple of pellets in the morning and a prawn in the evening. He always seems to be searching for food though, am I giving him enough??

Well having the use of mature media is great, technically no cycle needs to take place because it's already done and colonized with your denitrifying bacteria- assuming you have enough cycled media you can add your livestock right away and not have any problems!

The bacteria in your filter should be thought of as a living thing in itself, they need to feed constantly in order to keep the tank cycled. If they don't get a nice supply of oxygen and ammonia then they start to die off- pretty quickly. That is what you are seeing now because they won't have been fed for the four days the tank was sitting. It's a good part of the reason why fishkeepers panic when they lose their electrical supply as well

For the meantime just keep up with your water changing till you're back to being properly cycled (zero ammonia and zero nitrite).

You may want to hold back quite a bit on his feeding for the duration of the cycling process. The more food you give him (especially meaty stuff like prawn) the heavier the waste load and the more toxic the water will become until the tank has cycled- just means more work trying to keep the water good.

Thanks for the advice. I will cut back on his feeding for a couple of days and just keep up with the water changes. He is quite a messy little bugger! He seems fine, is very active and eating well, so far so good

No sweat, hopefully it will all be on an even keel soon.

I've always fancied a crayfish of some sort though they freak me out slightly!

He is quite freaky, the only downside is that now we have him we cant really have anything else but he is pretty fun on his own.

Was just doing Erics water changes and was clearing some poop off the gravel, I moved a rock aside to clean under it and found a rotten prawn

It must have got lodged under the rock somehow and rotted there instead of being eaten... could this be why my nitrite levels have been so high? Im sure it must have been there a couple of days.

Will have to very careful to check for manky prawns from now on!