Nitrate and phosphate rise???

[jfenton954]

I have a waterfall scrubber and had 4 23w cfl's on it for 18 hrs a day and the turf algae grew like crazy I had my tank for over 7 years now and the last 5 months or so the algae has been a red slime. That's changing the bulbs out every 90 day also. So I put a post on here a month or so ago and someone suggested I switch to 22 hours so I did and no change really. So instead of buying more bulbs I decided to upgrade to leds and rebuild my design. So I have 4, 3w led bars 2 on each side with a total of 16, 660nm LEDs and 2, 430nm LEDs on each side running 22 hours a day. The lights are about 2 3/4 inches off of the screen with a rio 1700 pump with very little growth after 2 weeks. My nitrate and phosphates are slowly raising. Here are some pics.

[SantaMonica]

Well that black growth looks exactly like weak light. At the very least, brush/scrape all the black stuff off because it blocks light and it stops GHA from attaching.

Maybe the LEDs are not as strong as advertised. To test them, you could put all 4 strips on one side.

[jfenton954]

Here is where I ordered them from. Let me know what you think.

http://www.expressions-ltd.com/Algae_Scrubber_LED_Light_p/led-grow-light.htm

[SantaMonica]

Yes I've seen that light before, is a good one and it has nine 1w LEDs. So you have 18w per side, compared with your previous 46 CFL watts per side. So it's just a wattage issue.

By temporarily putting all 4 of them on one side, you'll find the answer quickly.

Have you moved any of your rock, or changed anything flow in the display?

[jfenton954]

If that's true I'm really not trying to spend another $160 on more lights

[SantaMonica]

Still though, by putting them on the front you can at least have the front working well.

[jfenton954]

Is that going to be able to support my 75g tank? I shortened the screen to 7 1/2 x 10 inches.

[SantaMonica]

Well, sizing is a different question; read here:
http://algaescrubber.net/forums/showthread.php?1419-New-sizing-guidelines

[jfenton954]

Do you think I would be able to change the 1w leds to 3w in those bars?

[SantaMonica]

No the power supply will not work.

[jfenton954]

I know you are the leading expert on algae scrubbers SantaMonica and your advice has always helped me. I'm still trying to find a good way to mount all four light strips on the same side but why do you think his setup worked? Mine is built exactly the same way the only differences are he has a 220g tank, 550gph pump on scrubber, lights on 12hrs a day vs. 75g tank, 800gph pump on scrubber, lights on 22hrs a day

[SantaMonica]

If you mean the Expressions guy, he probably has lower nutrients in the water.

[jfenton954]

What do you mean by lower nutrients in the water? I thought that the screen would do better with higher levels in the tank so the screen would have more to feed on.

[Brent1128]

The sizing guidelines say for LED, use half the wattage. If he was at 46w per side before, half would be 23. He is at 18. Would a 5w shortage be that much a difference?

[SantaMonica]

Growth is illumination relative to nutrients. Higher nutrients need more illumination to grow the same green. If illumination is less (relative to nutrients), growth is dark. That's one reason why some scrubbers start out dark and get greener: because nutrients are coming down, but illumination stays the same.

[jfenton954]

Do you think a 50% water change would help?

[SantaMonica]

Sure. Anything that brings nutrients down, or increase illumination in an area, will help.

[jfenton954]

So basically doing a water change would help but if the wattage on my screen isn't strong enough, than the algae on the screen will slowly die off if the bio load gets to high in the tank.

[jfenton954]

So I kinda figured that a water change is only putting a small band aide on a large cut so I moved all the light bars to one side if that is enough I guess I'll have to spend another $160 on 4 more for the back side but if it doesn't work then I will have to build my own with more 3w leds instead.

[SantaMonica]

It would not die off; it would just grow dark slime and would not filter as much (and would be harder to clean).

[jfenton954]

So I moved all 4 led strips to one side for 3 weeks with all dark growth. So I figured go big or go home so I added 20 3w leds to each side for 60w on each side. Letting run 22 hours till I see good growth then will cut back.

[Brent1128]

Did you replace the 1w with 3w? Looks like you are still using the expressions LED strips.

[jfenton954]

I found similar heat sinks on eBay so they look the same. Look at the wires are different.