I have a 20 gallon tank... currently using air stones with a UG filter. What powerhead would you suggest I use? Will this be a big help to keeping the tank clean? Will it replace my air pump and air stones, or be used in conjunction with? Should I get powerhead with reverse flow or just regular? Do they aearate the tank more, less or same as air stones? Any thoughts would help, thanks

Miss those bikini bottoms spongbob!!!Hehehe!!! I would get a power-head that has a venturi (air entrainment) feature. This will replace the air-stone and pump. There are lots of different kinds/brands, but not a whole lot of difference in function. I've got a couple with the reverse flow feature but I've had problems running UG filters backwards so that is superfluous in my opinion. I suggest getting one or two power-heads that have a water deflector with witch you can direct the current upwards. This will help reduce excessive current. You could either get one larger one or two smaller ones. If you just get one you'll have to plug the remaining up tube on the UG filter. So yea, the venturi power-heads aerate much better than air-stones and they greatly increase the function of the under-gravel filter.

The power-head is going to pull the water up from the bottom of the tank just as the air stone is meant to suck water from the bottom of the tank inside the up pipe of the under-gravel filter. The water got to the bottom of the tank because it gets sucked down through the gravel first before it goes up the pipes in the back of your tank. The gravel itself is the actual 'filter'. There should be a screen on the intake part of the power-head to prevent large rocks and such from getting into and stuck in the impeller (propeller), so you don't need an extra filter for it (unless you're using the power-head by itself; in that case you can attach a sponge filter). Stick the power-head on top of the up-tube/pipe of the under-gravel filter (take off any attachments that are on the up tube/pipe) and then plug the power head's power cord into to the wall outlet. Remember to get a power-head that has an air tube that attaches to the power-head by where the water comes out. This is how air gets into the system to replace the air stone. Air gets sucked into the power head and is spit out with the water into your tank. You can adjust how much air gets into the jet of water because they come with an adjustable valve. Lastly, get a power-head that has a deflector that snaps onto where the water comes out. This will allow you to aim the water, and you can aim it in ways that reduce the current if it's too strong. Get a relatively small power-head(s) for a 20 gallon tank. Let me know if you end up having too much current. I'll give you some other ways to reduce the current without having to take the power-head back.

I have an acrylic tank where the top doesnt really have an area to hang powerheads on the sides where my tubes are, just an opening for wires. So I cant hang powerhead off the side, and im reading that the suction cups fail after few weeks. Looked into Sure Grip which makes magentic holders for three of the popular powerhead brands (Maxijet, SEIO and Tunze Streams). Are you familiar with these brands and do any include the features you mentioned were important for my setup? Thanks in advance!

got it, thanks

The thing with that arrangement is that when the gravel gets clogged up more and more with guck your one power-head will start overpowering the bubbles and water will start getting sucked down the riser with the air stone which is backwards. Then your under-gravel filter won't be working correctly. Unless you have very little gravel and very little resistance to water flow through it that idea won't work for long. It would be better to seal off the air stone side and just use the air stone for a bubble feature by itself.