going to build a better scrubber for myself!

Welcome to the site!

I design mine with one deep red for every 2"x2" of area (4 sq in), on each side. So a 4x6 screen has 6 on each side. you could go less though, about half of that would be the minimum I would do. Distance takes a little playing with also, I do 2" and then run them at 1/2 power or use a diffuser until the screen is mature, then go to full intensity, seems to work well.

Flow rate has always been ideally around 35 GPH/in of width. You can go lower, I've done it on my first scrubber and it worked very well, and I have also run subsequent scrubbers at lower rates, but I think the effectiveness is all inter-related. If you increase the flow, you can increase the photo period and intensity and get better growth and filtration. There is an upper limit to flow, generally anything over about 50 GPH/in of width is getting to the point of diminishing returns.

You can partially submerge the screen, it will still grow but with the waterfall portion right above it, it will take longer to 'get going' and then it may fill in nicely. If you mean make a huge area that is submerged, that depends on your setup. you have to be able to get light to that area that is submerged in order for it to work.

As far as pump vs overflow, I prefer pump because it's safer (no risk of a clog overflowing the tank) but overflow is ideal because the scrubber gets the first crack and the water. The issue is making sure that there is a secondary path for water to take if there is a clog so that your tank doesn't overflow. Adding a pump means adding heat, power, and space. So it's about choices really.

Hope that helps!

Bud

 

Well the cool whites are not useful for scrubbers. You want royal blues if anything, and then you need to knock them down in intensity.

At most you only need one RB for every 6 DRs

 

What was your bad experience with RBs in the past?

I understand your logic, but it won't work that way on the scrubber. The CWs have a much higher radiandt flux output per watt when compared to DRs. My first L2 had 6 DRs with 1 RB right in the middle. Everyone's screen was bare white in the middle. In fact I still run one scrubber that grows crazy amounts of algae every week but when I clean the screen, underneath the 1" thick mat of algae there is a bare white 1.5" diameter circle right in the middle. This is the primary factor, also that CWs do not give you very much if any useful spectrum for algae growth. If you were going to use any white, it would be WW 2700K. And ever with those (or any WW, NW, CW, RB) you are going to have to knock down the intensity relative to the DRs.

The DRs usually have a max current of 700mA. Run any LED that is inside of the Deep Violet or Deep red at half of this current, max. You can this by wiring 2 of them in parallel within the series string. This is what I do:





This above wiring technique splits the current evenly (depends on how well the pair is matched, but it seems to work well).

Alternatively you can use 1W RBs but I haven't actually tried that.

Reducing the current (or putting a diffuser in front of the array with a piece of black electrical tape directly over the non-DR LEDs) will result in the screen filling in very nicely.

 

Ah!! Welcome! Want me to change you over to greenmachine on here?

 

I would bother using CWs at all. Just half power RBs. The Chinese fixtures could have had multiple issues so don't let that steer you wrong

HD acrylic is too extruded which is fine, just don't get lexan or another polycarbonate

You can weld rough cut OK and just keep gooping on the WO. Use a standard (cheap) blade though, unless you want to pop for the triple-chip plastics blade (Diablo brand at HD). A 'fine tooth' or high-tooth-count blade will tend to melt more than cut.

 

Base it on feeding and double it at most. I just had a local customer in today so I could mod his L2 for threaded drains and he used to run a DIY SM100 on his 90, he said the L2 outperforms it easily if that tells you anything. His 90 is heavily stocked and fed and he was blasting the water through the L2 using a Rio 3100, probably flowing over 600 GPH. He said in 7 days his box was full and both drains going 100% and box filled to within 1/2 cm of the cutouts so he wanted to upgrade to the Rev 3 drains.

You can get a lot out of a small screen if you do it right.

 

L2 is 4x6, u bet he's feeding at least 2 cubes/day, but I'll ask

 

That's fine also, there's more than one way to kill a cat! The box/enclosure would be to prevent water spray and protect the lights, and a bottom plate would help keep algae where you want it and block light. You can always drape the screen in saran wrap to take care of the first 2 items.

 

Sounds good, but a pic would help me confirm for sure

 

High light level would be one DR on each side of every 2x2 section (4 sq in)
Normal/minimal would be half that (one on each side of every 8 sq in)

So your 5x5 screen - 25 sq in / 4 = 6 LEDs per side, or 3 per side for normal light. So you're right in the middle, should be fine.