cant get nitrates down

[bentleg]

Hi Guys
I need some advice on my scrubber, every week a get GHA and a good amount off of my screen but i cant seem to bring my nitrates down to 0 or any where near, they are about 10 to 15 ppm. and phosphate is always 0 or as close as i can see it to be (salifert)

i only feed 1/2 a cube a day and it all gets consumed within 5 min,

its 130 x 150 cm lit only on 1 side with a 10w led 8 red 1 blue

i run it on a 14 hour photo period and it get about 3000 gph flow,

Top up is done with RO.

visually it performs flawlessly the stuff i pull from the screen i have to do it every 7 days its so thick

thanks in advance

[Floyd R Turbo]

Got a pic?

Is it this one

http://algaescrubber.net/forums/showthread.php?2467-Bentleg-s-UAS-scrubber-design

http://sketchup.google.com/3dwarehouse/details?mid=75e474632bce18be76a95216b5490652

?

[SantaMonica]

You just need more scrubber.

[bentleg]

No I went with a waterfall in the end, bios starts on this page for it.
http://www.ultimatereef.net/forums/showthread.php?t=638772&page=5

[Floyd R Turbo]

Let's consider more detail:

1) did you err on your dimensions? 130x150cm is like 50" x 60". Did you mean millimeter? That would be more like 5x6. I'm thinking that is what you meant

2) your light is a 10W multichip, right?

3) UAS or waterfall? 3000 GPH or LPH?

Pictures??

[Floyd R Turbo]

A you beat me to it with your post. Just checked out the thread.

Are you having tank issues? N at 10-15 is not horrible, but some corals don't like any nitrate.

I would say increase the photoperiod, your screen is mature enough to handle a little more light.

Still wonder about the L vs G on the flow

[bentleg]

Flow is lph sorry.

I lost a zoa colony, but I think they were the famous melting hong Kong zoas but also 2 monti frags, they just bleached out but everything else is thriving.
Ive just ordered another led for the other side of the screen.

[Floyd R Turbo]

So are you really putting 750+ GPH over a 6" wide screen? Is that the actual measure flow? because that's a ton of flow.

[Floyd R Turbo]

Also going double-sided will help tremendously

[bentleg]

It's a 3000 lph return pump, with no bends and only 1 meter to travel so not a lot of head loss. The scrubber is gravity fed from the main down pipe on a twin standpipe overflow.

[Floyd R Turbo]

a 6" wide screen should have about 200-250 GPH over it. If you pump is in the neighborhood of 800 GPH, and then add in loss (which might be dependent also on return pipe size - the larger the less loss, the smaller the greater loss) you could be more like 400 GPH. When you say "main pipe of a twin overflow" are you talking about a primary + emergency type of setup? So this is on the primary which gets most or all of the flow?

[bentleg]

Yes its 32mm primary drain

[Floyd R Turbo]

Ok. I think based on that, it doesn't sound like a flow issue. Add the second light and extend the photoperiod a little. With those multichips you have to be careful about over exposure, so bump it up to 15 or 16 hrs/day and watch for signs of burning.

Out of curiosity, when you clean the screen, is there a bare/white spot right in front of the LED? Or is it pretty much filled in everywhere?

[bentleg]

No white spot or burning, just lush green gha all over the screen, anyways thank you verymuch for the advise

[Floyd R Turbo]

Good. Bump up to 16 hours