Algae Scrubber Basics

[parrotchute]

Hi Floyd, have a ? .. 3 days ago i upgraded from a 30g to a 75g, im using the same ATS from the 30g, the 75g looked great yesterday in the morning! i cleand one side of the ATS in the morning, when i got home at 9:00pm my sand and rock were full of hair algae!! :-( my nitrates are 0ppm and phosphates are 0.2, what happend??? Thanks.

For what it's worth, tanks with algae in them will often read close to zero on nitrates/phophates, esp with MORE algae in them. The algae is so efficient at taking up these nutrients that they often take it out of the water column so fast that you won't see results on the test.

I'd be willing to bet the scrubbers will cause the same phenomenom.

 

[KafudaFish]

What made the size guide shift to amount of feeding?

Thanks.

 

[redneckgearhead]

For what it's worth, tanks with algae in them will often read close to zero on nitrates/phophates, esp with MORE algae in them. The algae is so efficient at taking up these nutrients that they often take it out of the water column so fast that you won't see results on the test.

I'd be willing to bet the scrubbers will cause the same phenomenom.

Yes, they do cause the same phenomenon, that's why we are using scrubbers. We use the efficiency of the HA to remove these nutrients from the tank.

 

[Floyd R Turbo]

I think it was a common sense thing. As BlueScreenODeth pointed out, he ran a screen that was much smaller than his system and it worked fine, as it did with many other large systems. After a couple years of troubleshooting people's systems on various threads (there are dozens of sites with active threads) it became clear that the amount of food added to a system directly affects the growth on the screen. Also many people under-sized their scrubbers, intending for supplemental filtration and found out that, if built right, they worked pretty good for primary filtration.

Eventually it was determined by experimentation (by maximizing the feeding to the point of overwhelming a scrubber) that there was a definable amount of food you could add given the size of the screen and robustness of the scrubber.

IMO looking back on it, the original sizing guidelines had quite a bit of 'fudge factor' figured in. What that means is that someone can make one very poorly and still get decent results. I can tell you that I have seen some pretty poor designs that work just fine. With the newer guidelines, it is more important to build the scrubber well.

 

[KafudaFish]

Ok thank you. I found it pretty interesting when I checked back into this thread last week and the talk about feeding and sizing.

Just for fun I have a 1 x 3 inch screen sitting at my water's surface on top of my powerhead in my nano that gets some green algae.

I don't have algae in the display to be honest so it was more of a "I wonder what this would do" type thing.

 

[extra3d]

Hi Floyd, me again, heres some pics of the algae i was talking about, what do you think? thanks..

 

[Floyd R Turbo]

Almost looks like diatoms. That's usually the first thing to grow when you get an imbalance. Should pass. Wouldn't hurt to siphon it out to keep it at bay. It should come off pretty easily. You could also put a filter pad somewhere in the filtration system and blow it all off the rocks with a powerhead, give it an hour, then clean the pad.

 

[EnderG60]

any reason not to run a ATS off the skimmer outlet?

The flow rate on my skimmer is almost exactly what I need for the scrubber, and I would love to not need to buy another pump.

 

[Floyd R Turbo]

How do you plan on getting the water up to the slot tube? Unless your skimmer outlet is way up high, I can't see how it would work. Also the slot tube junction typically needs some pressure, whether that be from a pump or from a water column in the drain. Plumbing it directly to the outlet of the skimmer (sealed plumbing) would end up overflowing the skimmer the second any algae crept into the unpresurized slot junction.

 

[srusso]

How do you plan on getting the water up to the slot tube? Unless your skimmer outlet is way up high, I can't see how it would work. Also the slot tube junction typically needs some pressure, whether that be from a pump or from a water column in the drain. Plumbing it directly to the outlet of the skimmer (sealed plumbing) would end up overflowing the skimmer the second any algae crept into the unpresurized slot junction.

+1 you can't put back pressure on your skimmer outlet... It's not going to work if you do.

 

[EnderG60]

my skimmer is 12" diameter, 3 feet tall and on a table in the basement above the sump. there is at least 2 feet of head on the outlet which is valved way down anyway to control the water level in the skimmer. I dont see back pressure being an issue. algea clogging the slot and backing it up...yeah that would be a problem.

 

[Floyd R Turbo]

Well in that case, if you rigged up something with a break in between, like double-tee so that the skimmer effluent went down a pipe that fed the scrubber, and that pipe had a tee off to a open-drain with a half trap, that could work. Like this

This is my sketchup of an emergency overflow design for a overflow-fed scrubber, the idea being that if the slot clogged there would be another path for the water to flow. Same concept here except the purpose of the double-tee/double elbow is to eliminate back pressure on the skimmer, however unlikely that is. It also acts as a siphon break which is equally as likely with a direct sealed line from the skimmer.

Make sense?

 

[jimrawr]

Hi everyone, I am setting up my first algae scrubber, and was wondering if anyone could provide some feedback for me on what you see in my image. I also have a couple questions.

1. How do you drill for the water to drop onto the scrubber? Just a lot of little holes going across the length of the top PVC tube?
2. What size pump do I need? I am thinking of using a maxijet 900.
3. On the side of the ATS that isnt connected to the pump, should I take one end cap off the leg this way any water that doest drop onto the scrubber is released back into the sump, or should I keep it capped this way it is pressurized?

 

[Floyd R Turbo]

Review the basics for Q #1 & #2

Basics Write Up - Post #1
Updated Summary - Post #2001-2010
Quick Troubleshooting - Post #1902
Alternate/Updated Sizing - Post #2723

#3, cap it. You want pressure. maxijet 900 may not do it for you with that head depending on the width of the screen. Again review 2001-2010 for suggestion on testing the actual flow rate. With your setup this is rather easy if you have't welded the pipes together. Just put in a sink with water to the level of the sump, undo the horizontal pipe and put in a street 90, and fire it up and fill a pitcher and time it (discussed in detail in the 2001-2010 summary)

 

[srusso]

Review the basics for Q #1 & #2

Basics Write Up - Post #1
Updated Summary - Post #2001-2010
Quick Troubleshooting - Post #1902
Alternate/Updated Sizing - Post #2723

#3, cap it. You want pressure. maxijet 900 may not do it for you with that head depending on the width of the screen. Again review 2001-2010 for suggestion on testing the actual flow rate. With your setup this is rather easy if you have't welded the pipes together. Just put in a sink with water to the level of the sump, undo the horizontal pipe and put in a street 90, and fire it up and fill a pitcher and time it (discussed in detail in the 2001-2010 summary)

:hmm3: I think Floyd is being modest here...
There is no way in hell, a maxijet 900 will give the needed flow you need for that scrubber...

 

[jimrawr]

Yea you are right. I had a spare MaxiJet 1200 laying around and I just did a flow test on it, took 14 seconds to fill a 1/2 gal, so thats around 128gph of flow out of the ATS.

How can I calculate roughly the pump GPH I will need so I dont go off buying a pump just to see that its either way too high or way too low for the ATS?? Right now I am thinking a Mag Drive 7 (700gph) or a Marineland 1800 (475gph). I think the marineland still wont be enough flow but the Mag 7 should do it for me.

 

[franklypre]

I used a drimmel to cut the slot for the scrubber pad and it worked well, any router style cutting bit will work. I would suggest you check the head rating on the pumps you are wanting to purchase. And for the idea of rigging a ATS to a skimmer, well I gave it my all and ended up making several messes without any good results. Even with a gate valve on the skimmer it just never stayed tuned in due to the flux in flow. I have been using my scrubber for a few months now and it definately is something I will keep for a long time.

 

[JohnnyB in SD]

Yea you are right. I had a spare MaxiJet 1200 laying around and I just did a flow test on it, took 14 seconds to fill a 1/2 gal, so thats around 128gph of flow out of the ATS.

How can I calculate roughly the pump GPH I will need so I dont go off buying a pump just to see that its either way too high or way too low for the ATS?? Right now I am thinking a Mag Drive 7 (700gph) or a Marineland 1800 (475gph). I think the marineland still wont be enough flow but the Mag 7 should do it for me.

Required flow is based in screen width. What size screen you going to use?

 

[alaska clowns]

New pics and some spots

New pics and some spots

Two weeks ago I decided to increase my lighting. The bulbs are about 4 inches from the screen (which is 7" wide and about 10" long). I replaced the 23 watt CFL bulbs with 42 watt bulbs (1 bulb per side). Photo-period is 18 hours on and 6 off. The first week the algae growth increased and almost seemed to be getting green (mostly noticeable after I first clean the screen).

But the last day or two these spots are developing, and I'm wondering if you think I'm burning my screen?

Should I cut the photo-period in half at this point?

Does it seem like I have enough light to be effective yet? My DT algae problem is holding on...

Thank you!

 

[jimrawr]

Required flow is based in screen width. What size screen you going to use?

9" so flow of 324gph would be good after head loss