There are two internal water circulating pumps with internal filters having a goal to circulate the water to keep in shape anemones and oxygen them, fish and everything else in the tank. Also, filters in them catch some bio-mass remove it from the tank. One pump/filter is on the left side of the tank and the other is on the right side at the same height.
There are also some filters not in the main tank, but on the back part of the tank accessible only when the glass cover is removed.
The left water pump is on the top of blue sponge. There should be a piece of filter material attached to to the body of this pump. Look at it and remember how it is attached because you have to put it back! This is important! That little piece of material prevents anything to get into the pump – especially we dont want anemone to be ssucked into the pump and killed or if a piece of macro gets there it could ruin the pump and it could overheat and overheat the water in the tank – so it is important to monitor pumps if they are not stuck!
If they are stuck, they have to be stopped by removing white cable! Or see which black cable inside the white extension leads to certain pump! So, look at the filter material and slowly remove it and put it into plastic container. Now lift the right pump and hold it above water and slowly open the lower part and put it into plastic round container.
Untill further notice, leave the main water filter that is inside of the left lower compartment when the water comes to main tank as it is dont remove it. This is fairly cmplicated process and has to be done once every two maybe three weeks. If you wait more then water will slow down and might be blocked leading to general catastrophy in the tank and everything will die!
But for now do not remove it!
Take a black light and put it over the back of the tank and move it a bit here and there to see down the opening where the main water pump is. You should see the green/blue sponge on the right side and the pump with white meshy material on the left. Remove only the sponge on the right side and do it slowly not to disturb water too much and using flat stick from the drawer – one that has a curvy end – dig the sponge and using a hand remove the sponge and see if there is any sea star or small thing crawling on it – if there is anything – put it back to main tank.
Put the sponge to the white round plastic container. This procedure should be done together with water change! So, I will continue with water change chapter. Now, take round plastic container with filters and go to bathroom. Check visually if there is any form of life on sponges because there might be some liitle creatures that could be save in last second. If there is a small living thing grab it and put back to tank, please. I would close the sink so water will accumulate and see if there is anything to be save when you clean the sponge filters. Turn on warm water and simply wash dumping and banging against the wall of sink a few times and watch for creatures – often I find some sea stars or small snail or something moving and I grab it and put back to tank.
If there is nothing to save, just continue to rinse it and clean it. Especially, when you open the right filter, you may find many things...when filter are fine put them to plastic container and go back to tank and put them back to water pump. The right pump has a correct side and it will click when placed correctly – look for round opening... the sponge has a round opening inside itself – it should be somehow on the left in the cube.
Now, the left water pump – pay attention to its nose..it has to be placed towards the glass – best if you do not remove that part at all. Make sure the filter material is over the top of that part and blocks anything that might get inside the pump! Use some small wires to attach it firmly.. when finished placed slowly first green/blue sponge against the wall and place the pump onto that sponge so vibrations do not go into the body of tank and the second small sponge is still attached when you finish placing the water pump and it is not touching glass on the left or rock on the right!
The right pump is easier, but so important is the level of this pump! Make sure you remember how it was before you remove to clean. The level of pump creates water current that keeps big anemone in correct spot. When the pump is in a wrong level the anemone will be moved by current and while being in a different spot it might touch other corals and they will die from poison. I will place a green tape on the side of the tank to represent level of that right pump and keep that pump more less in this area.