Intro' and thoughts on this simple design

[Rumpy Pumpy]

Hi, I am Bill from the UK.

I've been looking for a way to reduce NO3 in my FW 55 gal tank for a while. I built a coil denitrator a couple of months ago but it was not very successful (I suspect it was leaking oxygen in somewhere).

Having been following this forum for a while I decided to have a go at building a simple scrubber.

One of my problems is that I have very limited room under the tank to accommodate, I have a sump, the design of which is not ideal, and there is not much headroom above it.

Anyhow, yesterday I cobbled together a simple canvas screen, suspended over the sump by hooks in the underside of the cabinet at one end and sucker clips inside the sump at the other (easy to remove for cleaning), water flow provided by a 12v powerhead and light by a single CFL bulb.

Here is a quick video of it in operation. It's been running for less that 24 hours so there is no growth so far.

http://www.youtube.com/watch?v=LXIFbTGBB5A&e

I think I'm going to have to incorporate a sprinkler bar to spread the flow of water over more of the width of the canvas and some better lighting (thinking of getting a couple of flexible necked LED desk lamps for that)

Anyhow, all thoughts and suggestions would be welcome.

[worley]

Hi Bill, nice to have another fellow Brit on the boards!
Is that the entire flow of water you have available? If not, higher flow would be good, as well as spreading it out more evenly across the screen.
I don't think the flexible LED lights will be anywhere near enough, so if you want more light, add a second CFL bulb, and/or move the other closer (watch that it doesn't get splashed of course, and don't forget RCD circuit breakers on all the fish tank equipment!).
Tom

[Rumpy Pumpy]

Thanks for the reply.

That is all the flow I currently have, but I reckon it will pass the entire volume of the water at least once an hour (my sump return pump turns it 15 or so times an hour). I suppose i could get a bigger powerhead or plumb the thing directly into my weir outlet somehow.

The LED lights I had in mind were the 240v spot types like this one



...used in a goose necked desk lamp so they could be placed very close to the canvas.

Would a couple of those be adequate?

[worley]

What (W)attage are the LED bulbs and can you find out the Lumens output too?
I would think you would need loads of those bulbs.
As for the flow, you need 35 Us gal/hour per inch of width on your screen, so if it's 12" wide, you want 420 us gal/hour or 1600l/hour to flow evenly across the entire screen
But as yours appears to be single sided you can half those values, so 210 us gal/hour or 800l/hour should do it. As it's single sided though, you need twice the area (and lighting) of a double sided screen lit from both sides

[Rumpy Pumpy]

What (W)attage are the LED bulbs and can you find out the Lumens output too?
I would think you would need loads of those bulbs.

Dunno. I saw some working last night and they were less than impressive frankly. Back to the drawing board light-wise.

As for the flow, you need 35 Us gal/hour per inch of width on your screen, so if it's 12" wide, you want 420 us gal/hour or 1600l/hour to flow evenly across the entire screen
But as yours appears to be single sided you can half those values, so 210 us gal/hour or 800l/hour should do it. As it's single sided though, you need twice the area (and lighting) of a double sided screen lit from both sides

It's currently delivering 1 litre every 13 seconds, about 280 litres per hour.

So I guess I'll be needing some more flow.

[worley]

You'll need four times that flow then, and as evenly as you can get.
At the moment compact fluorescent bulbs are by far the cheapest light output to power ratio in the short to medium term, as you'll need to replace the bulbs every 3-6 months they get a bit more costly, but I would think after 2+ years LEDs would be more cost effective in terms of not having to replace them and the fact that the newest ones are more energy efficient (light output per watt, and in terms of colour specturm) than compact fluorescent bulbs. I have still to dable in LED lights on my scrubber, but from the experiences I've seen on the forums here, you'd needs LOTS of very high powered LEDs and it's difficult to get the right mix of colours, distance etc so the colours merge etc.

[SantaMonica]

Flow is the main problem here. Get a bigger pump first, and put it in the sump.

But actually, I'm not sure I'd pursue a slanted screen at all. You are going to be tinkering and fixing and adjusting things for months, all while you are not getting any filtering. Really, I would just build a scrubber in a fashion that is known to work. And in your case, it would be a 2-sided screen of about 50 square inches, inserted into the water pipe, fed by a larger pump, and with at least a 23W CFL 2700K Floodlight on each side. This will give you the most filtering with the smallest size, and will be working in about a week.

[Rumpy Pumpy]

Flow is the main problem here. Get a bigger pump first, and put it in the sump.

But actually, I'm not sure I'd pursue a slanted screen at all. You are going to be tinkering and fixing and adjusting things for months, all while you are not getting any filtering. Really, I would just build a scrubber in a fashion that is known to work. And in your case, it would be a 2-sided screen of about 50 square inches, inserted into the water pipe, fed by a larger pump, and with at least a 23W CFL 2700K Floodlight on each side. This will give you the most filtering with the smallest size, and will be working in about a week.

Thanks for that. I was coming to a similar conclusion myself.

My problem though is lack of height.

I'm currently considering upgrading to a much larger tank, (probably a 6 x 2 x 2) which would have a lot more space underneath to construct a much bigger, more professional scrubber.

In the meantime, I might just let this one run as it is, purely as an experiment.

[worley]

I'm currently considering upgrading to a much larger tank, (probably a 6 x 2 x 2) which would have a lot more space underneath to construct a much bigger, more professional scrubber.

Exactly what I just did, got a 6x2x2 about 2 months ago with a 36"x22"x15" (15" high) sump, but haven't had the time to get the scrubber completed, so it's running on the old one for the moment.
Hopefully I should get it finished this week/weekend.

[SantaMonica]

Why don't you get the acrylic scrubber that greg is selling:

viewtopic.php?f=2&t=163&p=1141&hilit=sale#p1141

...it's exactly like mine, only 6.5 inches tall.