We became fishkeepers when my husband picked up this 55 gallon tank at a yard sale. Yup, there were two 15" pacu, four large oscars and two 12" plecos in the tank.
We spent about 1 1/2 hours every day vacuuming the gravel and sucking up poop, changing out about 60 gallons, replacing 15 gallons at a time with a five gallon bucket. We couldn't take out any more water, because the fish would have been out of the water. It got a little easier when we got a python, but we still had a lot of poop to vacuum out...we just didn't have to deal with the 5 gallon bucket. We were so sick of vacuuming substrate, that we vowed never to vacuum substrate again. The 300 gallon tank is bare floor. We have two "poop sucker" pipes that come down to about 1/4" off the floor. They remove all debris/feces off the floor.
Here's our mechanical filtration for the 300 gallon tank:
We use two Pentair Rainbow RTL-25 spa filters to remove waste from the tank. The system is powered by a Hammerhead pump. Besides the two poop suckers, there is a main uptake about 6" from the top. The two horizontal pipes on the right are the uptake lines from the tank. The tall vertical pipe on the far right is coming from a 55 gallon tank mounted on a high overhead shelf. It has a pipe going basically to the floor. There is a utility sink on the left side with a line running up to the 55 gallon holding tank. To add water to the tank, we just open the valve, and water gravity flows from the holding tank, through our mechanical plumbing and into the main tank. We also turn on the faucet of the utility sink, simultaneously refilling the 55 gallon holding tank while it drains into the main tank. We keep water in the 55 gallon tank so we can quickly add more water to the main tank when the water level drops in our wet/dry filter.
The most important feature of our plumbing is the little pipe on the extreme right behind the tall vertical pipe.....it runs down under the house and out to the patio. We open up the valve outside the house to remove water from the tank. Water is removed from the tank via the poop suckers, gravity flowing and draining outside our house. We could literally drain the whole tank in a manner of minutes, so we watch the water level and shut off the valve before the water gets too low. The tank has been running over 6 years, and there has been NOTHING to vacuum up. Love, love, love our system developed out of desperation.
We added extra holes to the top of our tank to accommodate our extra filtration.
In the front is a poop sucker on the right, and return for the mechanical filtration on the left. Then there is the return from the FX-5/UV sterilizer, another poop sucker, and at the far end of the tank is the main uptake, and the return from the wet/dry filter. When we refill the tank, once the main uptake is submerged, we turn the Hammerhead back on and pump in the rest of the water (it's faster then just gravity feeding the water in)
Here's old video of a water change:
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Love our spa filters so much, I have to use them on our big system. We're going with 6 RTL-100s, six 1 1/2" PVC poop suckers using two Hammerhead pumps.
New system has hot/cold water plumbed directly over the tank, and water lines to the sump and to the utility sink. We will be able to add water directly to the tank or to the sump.
We have two 3" floor drains for easy purging of the Ultima 4000s, changing out water, and/or setting up a drip system.
We love our fish, but tank maintenance is NOT our thing. What we had to deal with on that miserable 55 gallon tank has scarred us for life. We hate tank maintenance will go to extremes to avoid it.