Been having trouble with the pump clogging up. Noticed a lot of fish waste going into the gravel beds. I realized this was due to the cat fish I was keeping in the lower tank. Nothing was filtering their muck. Ive now transferred them all into the 200 litre blue tank joining the existing fish. All seem happy enough. Now Ill monitor the cleaning out of my filter bucket and see how we can add some more improvements over next coming weeks. They system is beginning to resemble something out of a mad professors laboratory with odd pipes here and there. Ive got far to many holes in the blue tank and lots of stop ends etc. I even turned up the main discharge pipe upside down to get a higher level of water in the tank. It must have about 170 litres in there. Cannot go much higher without overflowing.... Still it is working and thats the object of it all.