Algae Scrubber Basics

[Floyd R Turbo]

It's mixed bag, some running only a scrubber, many still run a skimmer (it will tend to skim less/lighter over time, and you may not need to run it 24/7), usually GFO gets ditched once P is under control but depending on the specific situation (GFO also takes the P out that algae needs to grow, so too much can inhibit screen growth, leading to N), some GFO may be needed (much smaller amount, run for much shorter time), ozone is fine AFAIK, carbon dosing/biopellets are sort of the opposite on the filtration spectrum and tend to compete with scrubbers, but you can do both

 

[srusso]

It's mixed bag, some running only a scrubber, many still run a skimmer (it will tend to skim less/lighter over time, and you may not need to run it 24/7), usually GFO gets ditched once P is under control but depending on the specific situation (GFO also takes the P out that algae needs to grow, so too much can inhibit screen growth, leading to N), some GFO may be needed (much smaller amount, run for much shorter time), ozone is fine AFAIK, carbon dosing/biopellets are sort of the opposite on the filtration spectrum and tend to compete with scrubbers, but you can do both

Well said

+1

 

[Reg the reefer]

It's mixed bag, some running only a scrubber, many still run a skimmer (it will tend to skim less/lighter over time, and you may not need to run it 24/7), usually GFO gets ditched once P is under control but depending on the specific situation (GFO also takes the P out that algae needs to grow, so too much can inhibit screen growth, leading to N), some GFO may be needed (much smaller amount, run for much shorter time), ozone is fine AFAIK, carbon dosing/biopellets are sort of the opposite on the filtration spectrum and tend to compete with scrubbers, but you can do both

Thanks, for your reply.

 

[percula99]

I have been running my waterfall type ATS (which I need to stick with due to space limitations) for over a year now. I get strong algae growth, but of the dark matted variety, not a green hair algae. I clean the screen once a week. My screen is 13X13, lit both sides with 150 watt 2700K CFL bulbs. I use a Red Sea skimmer pump rated for 525 GPH, although I think it is only giving me 300 GPH after my last test today. My nitrates are between 20-40, depending on how long it has been since my last water change, and phosphates are around 0.25.

A year and a half ago I cooked my LR due to soaring phos and nitrate readings. Once finished both were reading 0. That is when I implemented my ATS. Over time readings have slowly creeped up, even with the use of my ATS. Is my screen too big, not enough flow, low lighting?? Any suggestions at all would be appreciated.

 

[percula99]

I forgot to mention I feed 2.5 sheets of nori per day as well as 3 cubes. The sheets are 7.5 X 7.5 = 56.25 sq. in. X 2.5 sheets = 140 sq. in. I minus 30% because there is that much stuck in the veggie clip that the fish don't eat which equals 98 sq. in. That would be equivalent to 10 cubes, plus the 3 cubes equalls an equivalent of 13 cuber per day.

I have read through the guideleines but I find it confusing, which is why I am askling. Sorry...and thanks if you can help.

 

[srusso]

without seeing it, sounds like a lighting issue. Can you post a picture?

 

[percula99]

Hopefully a picture will help. Here's two, front and back of sump. I am not a great photographer, so let me know if you need more. In the second picture you can see the pipe on the right coming up from the pump and taking a 90° turn to go horizontally across to the waterfall. The lights are on 18 hours/day on a reverse cycle from the main tank lights. The screens were cleaned a couple of days ago.

 

[Floyd R Turbo]

Are you using 150W equivalent lamps? It looks to me like those are 23W actual, if that is the case, you're way underlit. You're right on for the screen size calculation. But you would want a total of 169W on the screen, minimum. Also your flow would need to be 13x35=455 GPH so that may be contributing as well.

It looks to me like you need more flow and more light, both in total and evenness across the whole screen - because you're only hitting the middle of the screen.

 

[percula99]

Yes, I am using 150 watt equivalent bulbs, but they are 43 watt actual. When you say I would want a total of 169W on the screen, minimum, do you mean per side, or total for both sides?

The water flow is falling across the entire screen. It may not look like it in the picture, but it is. There wouldn't be algae across the entire screen if it wasn't. I am retired now and trying to keep aquarium costs down. Gotta keep the wife happy. I have a MAG 3.5 which is only 350 GPH. If I cut the screen down to match this flow, would this work?

 

[Floyd R Turbo]

Yes, I am using 150 watt equivalent bulbs, but they are 43 watt actual. When you say I would want a total of 169W on the screen, minimum, do you mean per side, or total for both sides?

You go by actual, not equivalent wattage. Generally, you want total wattage to match or exceed screen dimensions. This means 170/2=85W per side, minimum. So I would add another 43W on each side. To get this to work in the space you have, you might need to cut the reflectors so that they can overlap like a figure 8. You might need to also back them off about 1". That will help green it up. You are using nice big reflectors so that is also good. Nice setup.

The water flow is falling across the entire screen. It may not look like it in the picture, but it is. There wouldn't be algae across the entire screen if it wasn't. I am retired now and trying to keep aquarium costs down. Gotta keep the wife happy. I have a MAG 3.5 which is only 350 GPH. If I cut the screen down to match this flow, would this work?

You could do that, but at the expense of losing filtration. The water flowing evenly across the screen is important, so you have that going for you. I ran one scrubber with 20 GPH/in and it did relatively well, but when I increased the water flow it grow tremendously better. When you increase the light, the lower flow may become more apparent as an issue, as the algae may turn yellow, in which case you would run the lights a few hours less. But I would pop for a Mag 5 or an Eheim Compact Plus pump because they are quieter and cooler (Mag pumps are basically a tank heater, I took mine off and it dropped 2-3 degrees)

Flow across the entire screen is one thing, if you can lift the screen out of the water and you get a continuous sheet of water falling off of it (no channelling or rivering off the bottom edge) then that's enough flow. If it streams and trickles off, that's not enough flow. Not only does the flow provide nutrients and CO2 to the algae, it also draws away the O2 it produces so that the algae can grow more. So you want a lot of flow, it is very important.

 

[percula99]

You go by actual, not equivalent wattage. Generally, you want total wattage to match or exceed screen dimensions. This means 170/2=85W per side, minimum.

Thanks for the invaluable info Floyd. I am thinking of buying some EShine 4G LED Growlights. Does LED lighting equate equally with CFL lighting watt for watt? I seem to recall you stating that LED was worth more. There is the 1-12X3W for 36 watts, or the 1-24X3W for 72 watts. Would either of these be OK?

 

[Floyd R Turbo]

So far, my feeling on LED is that if you take the "nameplate" rating of LEDs, you can use half of the wattage and get pretty close to equivalent, as long as those LEDs are the Deep Reds (660nm). So if you need 85W per side, you would want 40W of LEDs, or in your case, about 12 3W chips. The downside of LEDs (w/r to scrubbing) is that they are point sources, so in order to get even coverage you need to have them either evenly spaced without lenses, or set back from the screen with lenses. Most stock fixtures are not scrubber-friendly.

On the other hand, if you match watt-per-watt, then you would put about 80W of LED on each side and would have a "high light" screen, meaning you have double the intensity, and then you can run the lights on a shorter daily photoperiod. IMO, if you put one of those 72W fixtures on each side of your screen, you would only need to run them 10-11 hours/day. It would probably be a good idea to put a diffuser in front of the fixture and put it close to the screen.

Just pulled up the 4G 72W fixture and that looks decent, probably would work pretty good for your setup. Downside is protecting the fan from sucking in salt spray (inevitable).

Could DIY a pretty good fixture for the same price I bet, and you would be able to get better coverage and results, without an active cooling fan. Just sayin. That's why I stopped shopping for the perfect out-of-the-box scrubber fixture, Steve's LEDs has Philips 660nm chips for $3.49/ea, so with heat sinks, LED, driver, adhesive, etc you can build an adequate set of fixtures for <$200 easy, which you will blow through quickly with the e-shines.

 

[nbelohlav]

Mr Floyd YGPM

 

[Floyd R Turbo]

I don't know, Y not GPM? LOL

sorry I am young enough to know that is an acronym but too old to know what it means.

edit: ok google is my friend. I guess that acronym is the modern version of AOL's "You've Got Mail"

 

[nbelohlav]

it means "you got private message"... lol

 

[nbelohlav]

if i have my screen at 7 x 7 for 49 sq inches and i take that and multiply 49 by 35 GPH that is 1715 GPH that i will need to run over the screen... that doesnt seem right....

 

[inky]

if i have my screen at 7 x 7 for 49 sq inches and i take that and multiply 49 by 35 GPH that is 1715 GPH that i will need to run over the screen... that doesnt seem right....

Nope, it's the horizontal width, therefore 7 inches x 35 gph

 

[nbelohlav]

Nope, it's the horizontal width, therefore 7 inches x 35 gph

your a life saver, i thought i was going to have to add another Mag 9.5 to my sump just for the dang ATS...

 

[srusso]

your a life saver, i thought i was going to have to add another Mag 9.5 to my sump just for the dang ATS...

Nope, inky is right. 35GPH per inch of screen width.

Can you use the overflow for the scrubber? Thats what I do and wouldn't want to do it any other way.

 

[nbelohlav]

Nope, inky is right. 35GPH per inch of screen width.

Can you use the overflow for the scrubber? Thats what I do and wouldn't want to do it any other way.

i was told it is a real PIA to do it that way cause its really hard to dial in properly... and on top of that i just paid for the pump that i am gonna use so...