Algae scrubber help

[little_fish]

I know there is a super big thread on this already, but im kinda suffering from information over load looking at it. So i was hoping that i get this all on one place and hopefully a little simpler as well.

Below is a pic of my stand. I can only fit the 5 gal bucket in there, which is why im going with the scrubber instead of a skimmer. Im thinking i will use a piece of screen 10 in x 10 in, so i will only need to light it from one side.

Because my tank isnt drilled i will need to have an overflow. If im pumping water from the bucket back into the tank at the suggested gpm, does that mean water will be flowing over the scrubber at the same speed?

Also, how do i size overflows? I have also heard that they can cause a tank to empty if there is a power failure, how do i prevent this? Also if the water continually flows then how do I remove the screen to be cleaned?

Any help and very detailed pictures would be much appreciated.

 

[Zissou]

With a 10" screen, according to santa monica's recommendations you'll need at 350gph of flow to wash over it. An eshopps overflow (pf800) here should work: Reef Aquarium Filtration: Eshopps Overflow Boxes

On your return line, you'll want to make a siphon break hole just under the water level. When the power shuts off, this will ensure that the return line doesn't cause a siphon into back into the sump. The water level in your tank will recede back into the sump until it hits the siphon break; air will get into the line and cause the siphon to stop. You might want to make two of them just in case one clogs with debris or algae, always make sure this hole is clear:

The overflow itself can cause a flood if it gets blocked, say by a snail or something. If the overflow blocks, water can't exit the fish tank. Therefore, while your overflow is blocked and can't remove water, your return pump is still pumping all the water from your sump into your tank. Since that water has nowhere to go, it'll flood over the edges of the tank and onto your floor. As long as the overflow and siphon breaks stay clear, you'll be fine.

As for what size return pump in your bucket, that might be tricky. Too big of a pump and it'll run dry. Maybe an eheim 1250, or something in the 300gph per range to start out with. Hope somebody else has recommendations on this one.

 

[little_fish]

Thank you, i didnt realize that the overflows were sized or quite how they worked!

 

[Zissou]

The overflow only gets as much water as the return pump pushes back into the tank, and you just want to make sure the overflow can handle it. Now that I think about it, the eheim 1250 might not be enough pump for the screen.You might have to get something just a little bigger. You can tee off the return line or install a ball valve to throttle back the return pump if it's too much.

Oh, to change the screen on the scrubber, just shut the return pump off. The water level in your display tank will start to drop, flowing back into the bucket before hitting the siphon break, and then it'll stop. The overflow itself will also stop. It'll keep the siphon but it won't flow any water. Just pull the screen, do your cleaning, reinstall it, then turn the pump back on. Once the return pump has pumped the extra water out of the bucket back into the display, the water will rise back into the overflow and then it'll continue as if nothing happened.

 

[little_fish]

Ya, i can always alter the size of the screen to fit the overflow, but im looking around to see if i can find any other overflows rated for 350

 

[Zissou]

You mean return pump. The overflow is the thing that hangs off the back of your tank, it doesn't really matter how large or small it is, your only concern is that it can handle the amount of water you want it to move. A 1500gph overflow means it can handle 1500gph of water moving through it, but you can pair it up with a 600gph return pump and it'll move only 600gph through it. How much water it can move is dependent on the size of the return pump, not the overflow itself.

If you overflow is too small for your return pump (say, a 300gph overflow with a 800gph return pump), it'll quickly be overpowered by the water trying to flow into it.

So, if you want 350gph of water to be moved through the overflow (and therefore, onto your screen), you'll need a return pump that can move that amount of water. The water level in your display will then 'overflow' into your overflow at the rate it's receiving the water from the return line.

Sorry for the confusion.

 

[Piratefish]

You will be so happy with your scrubber. I love mine!! I have not done a water change for 3 months.