Hi Tessy,

Not a silly question, but, yes they're the right sponges. The U4 sponges are white.

thankyou noodle

Hi
Does this mean that I can dispose of the sponges,I am about to set up a new 180ltr tank with external filter and could substitute at setup

Deckrat

Does anyone have any tips on using a gravel vacuum? Ours says to move the vacuum section rapidly up and down until the syphoning process starts. This really doesn't work and we had to resort to a strategic suck. Anyway, hoovered around all the gravel, lifting up sections and trying to get all the visible bits, until 30% water had been removed and then replaced with decholrinated water. There's still loads of debris now swirling round the tank and I'm worried we're not doing it properly... Our White Cloud Mountain Minnows are quite agitated too and I'm worried it's stressed them out.

I bought an Algarde Syphoning Set from LFS. The squeeze bulb gets the syphon started more easily than the swirling around/jiggling about bit and could be put into my gravel vac to make it the correct size.

I also tend to go section by section in the gravel and on the plants/ornaments. Sometimes I don't get it all done before the water has come out, so I do the bit I missed first and more thoroughly next time.

Mostly it just takes practice. HTH.

Thank you Sarah. Then practice we will... x

Hold the whole siphon set underwater until all air pockets are gone, then cover one end to keep the water in the tube while you take it out of the tank to point it over a bucket or window. Keep the other end underwater at all times, and when you uncover the first end the siphon should start. This is how I have always done it and it usually always works.

Hi all
Quick question with regards to my filter. I have a Fluval U3 filter which I havent cleaned for about 6 weeks due to cycling the tank. Now that I have fish in there I was planning to do it this weekend. In it I have two white sponges and some polywool. From reading this thread I am guessing I change one of the sponges and wash the other in water from the aquarium. Do I also chage the polywool at this time or do that seperately at a later time?
Thanks

No need to change the sponges, just rinse in tank water angd reuse. They don't need to be replaced unless they're falling apart - takes years Replace the polywool whenever it gets dirty.

You will only remove damaging amounts of beneficial bacteria colony's if you scrubbed the gravel, the benefits of keeping the aquarium floor free from fish waste by far outweigh the small loss of beneficial bacteria.