I've encountered a dilemma when doing my own fish tank filtration! Please help me to solve it again! Thank you!

First the topmost tank make a downpipe with pvc pipe on the left side, the top surface of the pipe is flush with the water surface, and the bottom is connected with the hole at the bottom of the tank~~

The second tank make the same downpipe on the right side, and the third tank make the same downpipe on the left side.

The last one is the bottom tank~~

The bottom tank is made into three to four partitions from the left to the right, put filter cotton, glass ring, activated carbon, coral sand and other filter materials, the rightmost is the pump, the water will be pumped through the pvc pipe directly into the first tank~~

The whole process of the cycle is over~~

The balance of the water out of the tank is done by gravity, and the bottom tank's The water is pumped into the first tank through the pump how much will overflow out how much to the second tank, the same overflow out to the third, the same overflow to the bottom tank, if the power outage, the water will stop circulating, but there will not be a tank becomes empty ~~

General ornamental fish stores are such a filtration ~~

This kind of filtration is mainly biochemical filtration, the physical filtration ability is not very strong ~~ but can be improved ~~

Your ability to express yourself is better than mine, at least I can understand what you're asking, but I don't know if you'll be able to understand my answer~

Oh, I'm the owner of the world's largest ornamental fish forum, the Ornamental Fish House's Large Fish section!

Or directly qq or baidu hi find me~~

Good luck~~