Advice needed regarding major Tank Overhaul

Hi Everyone. Love the Forum. I need your help!

I have a Rekord 70, Jewel Aquarium which I initially set up 3.5 years ago. I'm very fond of having nice healthy green plants to compliment my neon tetras. So, when I set up the tank I used a half inch thick layer of Aquatic Pond Compost on the recommendation of my LFS. This was sandwiched between 2 layers of light filter sponge and gravel.

This all worked well and I had a nice tank until about 4 months ago. Something has gone very wrong and now my tank is always dirty with fine brown sediment which collects on the surface of leaves, bogwood and the gravel and looks awful. No amount of siphon suction cleaning is solving the problem; I can only do so many because of the fish. The water itself is perfectly clear and the fish seem very healthy and happy. My thinking is that the fertiliser has degraded and is escaping into the tank water. I think I need to empty the tank and start again.....

So, what I need to know is:

a) Is this normal? Do most people have to restart their tanks every few years?

b) Can I do this in a few hours? My concern is disturbing the nitrogen cycle. I was thinking I could save 40 of the 70 litres of tank water in a couple of large buckets: One with the fish and heater and one with the filtration system. Then I could empty the tank and clean it thoroughly and replace the clean substrate and plants. After this I would put back the filters, original water & Fish followed by 20 litres of new water.

c) If I do this, should I add a fresh layer of Aquatic fertiliser? Could this be bad for the fish as last time I was able to cycle the fishless tank for a few weeks?

Thanks so much for reading. Any advice would be greatly appreciated. I don't want to have to give-away/sell all my fish and wait a month to get the tank going again unless I really have to.

Never tried this fertilising method myself.
Just a thought but have you checked the filter is working properly, 3.5 years is a good long stint for a filter.

Thanks for the reply. I assume the filter is working fine. I change the sponges as recommended and the pump works. Not sure if it worked better when I bought it. How often should pumps be replaced?

This could be done a number of different ways so i will suggest one and see what you think.

1. As you said keep the 40l of water in buckets and remove the filter media in to one of the buckets of water. this will need to be aerated to keep the colony of bacteria alive while you work on the tank.
Do not clean the media.

2. Remove the fish into the buckets. These will need to be covered to stop the fish jumping while your back is turned.

3.Remove the gravel to a half bucket of tank water were you can clean it ready to go back in the tank.
Do not clean the gravel in tap water. It will contain beneficial bacteria along with possible nutrients for you plants.

4. now you can empty the tank and give it a clean.

5. Time to put it all back together again.
You could purchase a plant substrate from your lfs for the plants or a verry simple and basic way is to put a sprinkle of moss peat on the base of the tank before you replace the gravel. This is only a pinch of moss peat. The amount that you can fit between 3 fingers should be enough. This is a verry basic method of fertilising the plants and a proper fertilized substrate would be better.
Any way back to the tank.
Add the gravel. place the filter media back in the filter.Add the replacement dechlorinated water and any other water you have left over leaving the fish.
Put your plants and decor in. Top up the tank and start the filter.
When the tank is at the right temp. and it is not to cloudy Add the fish.

This should not take to long to do but leave a day to do it just in case something dosent go according to plan.

dantheman wrote:

Thanks for the reply. I assume the filter is working fine. I change the sponges as recommended and the pump works. Not sure if it worked better when I bought it. How often should pumps be replaced?

Just one thing that occured to me.
When you are changing the sponges 'as recommended' are you throwing them all out at the same time?
If so you are throwing out your whole biofilter in one go.
Also, the 'as recommended' frequency is only to get you to keep buying their products, the only thing that needs to go out on time is carbon I believe. Rinse the sponges in tank water instead of throwing them out.

Thanks for the advice! I would have washed the gravel in tap water and not kept the filter media aerated. I'll go with your recommendations.

Thanks again!

No worries dan. Any more questions just ask away.
There is always someone around to help.

Didihno wrote:

Just one thing that occured to me.
When you are changing the sponges 'as recommended' are you throwing them all out at the same time?
If so you are throwing out your whole biofilter in one go.
Also, the 'as recommended' frequency is only to get you to keep buying their products, the only thing that needs to go out on time is carbon I believe. Rinse the sponges in tank water instead of throwing them out.

Thanks for checking. No, I change them as recommended by sites like this. Just like you are saying. Cheers!