ApacheDan;805794; said:
a self-cleaning, pooper-scooper??....like the idea

could you please elaborate in your innivative plumbing?
In August 2005, my husband came across a 55 gallon tank at a moving away yard sale. The tank was chock full with eight big fish--four oscars, two 15" pacu, and two pleco. We were newbies who had to get online to find out which were the pacu and which were the oscars. Once we learned about the nitrogen cycle and keeping nitrates low, we were spending many hours every week doing 100% water changes every day. It took over an hour a day just to vacuum the feces out. We could only change out about ten gallons at a time, because of fish density. When we were setting up our 300 gallon tank, my husband was determined to make it as maintenance-free as possible. To accomplish this, we chose to have a bare floor in the tank. Besides the main mechanical uptake, we have two "poop suckers" strategically placed where the debris tends to eddy and swirl. These are 1" pvc pipe covered in black hose placed 1/4" from the floor. Debris and feces quickly drift across the floor and is removed from the tank. Here's a poor pic taken with a slow digital camera:
The honest truth is that the first poop sucker prototype was very ugly and unsightly. It was a grid of pvc in an E shape which lay on the floor of the tank. A bunch of holes had been drilled into the pipe. I was glad when the grid was removed from the tank. By that time, we knew where the debris was going to concentrate. The Reeflo Hammerhead is a 1/3 HP, 5800gph pump which really circulates the water. There is a very strong current in the tank, which I'm sure, helps to move the debris along the floor.
The tank is not self-cleaning, but it is an extremely low maintenance tank. There are valves placed on all the pipes. On water change day, the pump is turned off and the valve to the drain pipe outside the house is opened. The water drains outside by gravity flow. We can dump 100 gallons in about 5 minutes. Earlier this year, we discovered that if we closed the valves to the main uptake and the poopsuckers, the water is siphoned up through the return nozzle in the tank. The water then backwashes the spa filter cartridges before being dumped outside. Of course, this only works for the first couple of inches of water, as the return nozzle is soon out of the water. The valves on the three uptakes are then reopened to quickly drain the tank. To expedite the refill process, we have a 55 gallon tank sitting on a high shelf in the filter room (a converted old furnace room directly behind the tank). It is full of heated, conditioned water. There is a pipe running from this tank to the mechanical filter system. We have a hose running from the utility sink up to the 55 gallon tank. When we're ready to fill the main tank, we open a valve and water gravity flows into the big tank, we also turn the water on at the sink to keep filling the 55.. If we've only removed 100 gallons from the main tank, we can very rapidly pump the water into the tank. If we remove 200 gallons, we don't turn the pump on until the main uptake is back in the water again. Here's a picture:
The tall vertical pipe on the far right is the line from the 55 holding tank. Directly behind it you can see the pipe which goes down and under the house and then outside to our patio--that's the dump line. The three horizontal pipes, each with valves, are the uptake pipes, and the oblique pipe behind the filters is the return line. There are also valves on the uptake pipes at the tank (safety).
This is a system strictly for mechanical filtration. It has far exceeded our expectations. I really didn't think it could be done--but I'm a believer now! We have a large ProClear wet/dry filter for biological filtration, and an FX5 with a UV sterilizer for redundant backup filtration. We have consistently had great water parameters with the nitrate usually around 20 ppm at water change time. This is phenomenal with our "overstocked" tank. I truly believe the solid wastes are removed from the nitrogen cycle. On another thread on this forum, someone said that unless we changed out the filter cartridge at every water change, we would be adding to the nitrate level. We've been changing the cartridge every two to three months when the water clarity changes. It's crazy and impossible to have nitrates as low as we have it, with all the feces and debris in the filter cartridges....which is why I say that the waste is not part of the nitrogen cycle once it is out of the tank. Just today we got a filter cartridge cleaner which will enable us to clean the cartridges and reuse them. I really don't think it will make a difference to replace them at every water change (we change out 200 gallons every Thur and Fri to get the nitrates super low).
The bottom line is that our spa filter system has enabled us to have the low maintenance system that we desperately wanted. A boatload of canister filters would not have achieved what we wanted and needed. We're happy, and our fish are thriving..they all love the swift current and the highly aerated water. The system periodically spits bursts of air which we caught in this pic: