Algae Scrubber Basics

[Christian J]

When it comes to roughing up screens, I recall Paul B mentioned that he used cement in his trough. How about using things like kalk wasser to make the the screen more algae friendly substrate? Maybe that would even make roughing up unnecesary?

[Floyd R Turbo]

I'm not sure what Kalkwasser has to do with it. Roughing up the screen provides a physical area for the algae to attach and hold on. It has nothing to do with chemical reactions, and it is not a substrate from which the algae grows.

[srusso]

Originally Posted by Floyd R Turbo

I'm not sure what Kalkwasser has to do with it. Roughing up the screen provides a physical area for the algae to attach and hold on. It has nothing to do with chemical reactions, and it is not a substrate from which the algae grows.

Thank you for taking that one Floyd, I didn't know how to answer that one.

Christian, maybe you could elaborate?

[fppf]

Woohoo!!! Only a day in and there are little green specs!
Never thought I would be happy to see algae!

[BluScrnOdeth]

I know this is for phytoplankton, but they are all algae and i think would constitute them to being the same. I remembered reading this a while back because i'm about to get into growing my own phyto. This is why it is needed to have a 6hr dark cycle.

"Remember cellular growth and protein production occurs during the plants dark cycle and if we were to illuminate for 24hrs we would not increase our yield of phytoplanktons proportionally"
http://www.advancedaquarist.com/issu...02/breeder.htm

[kdirk]

Originally Posted by mrbncal

Nice looking, very cool idea. Where did you find those light fixtures?

Staples


http://www.staples.com/Black-Goosene...product_571213

[g8gxp]

how is everyone making the slit in the pvc pipe? i used a dremel and cut a 1/8 inch slit but i don't seem to be getting full coverage down the sheet. the water sheets well in the middle, but the sides seem to just get a bunch of little rivers of water. I've tried 4 or 5 different designs, the one i am using now is where i drilled little holes all the way across which seems to work, but the problem is that the algae is growing into the holes making it a pain to clean.

I know the slit is the right way, but i can't get the full coverage, is it because the pump isn't powerful enough? it's a maxijet 1200. or maybe it's that i'm using 1/2 inch pipe? too small diameter?

[CLINTOS]

I really like kdirk design

Maybe a little bit of a thinner box so the light's are closer. unless it would increase the temp too much.

[fppf]

Yeah I wonder if being near that window was a bad idea now.
I have my cycle reverse of the DT as everyone recommends. I wonder if the little bit of light that actually comes in the basement window will hinder the dark side, LOL. I was going to wrap the container in some foam insulation to prevent the condensation I'm getting now. That should block out most of the light.

I used 1" pipe for my cross tube.
To cut the slot I use a rotozip. The bits are 0.125" in diameter so it makes a perfect slot in one pass. I made a jig with a little 2x4 and 1x4 and clamped the pipe to the 2x4. One straight pass and done.

[srusso]

Originally Posted by g8gxp

how is everyone making the slit in the pvc pipe? i used a dremel and cut a 1/8 inch slit but i don't seem to be getting full coverage down the sheet. the water sheets well in the middle, but the sides seem to just get a bunch of little rivers of water. I've tried 4 or 5 different designs, the one i am using now is where i drilled little holes all the way across which seems to work, but the problem is that the algae is growing into the holes making it a pain to clean.

I know the slit is the right way, but i can't get the full coverage, is it because the pump isn't powerful enough? it's a maxijet 1200. or maybe it's that i'm using 1/2 inch pipe? too small diameter?

I would say the flow is not strong enough. Also some times when your screen is roughed up unevenly it becomes a little wavy. This could also create even flow. Please post some pictures of your setup that will help us get a clearer understanding of what maybe happening.

[srusso]

Originally Posted by CLINTOS

I really like kdirk design

Maybe a little bit of a thinner box so the light's are closer. unless it would increase the temp too much.

The lights should always be ~4 inches away. Closer and you will burn/bleach the algae. The lights become too strong in one spot.

[srusso]

Originally Posted by fppf

Yeah I wonder if being near that window was a bad idea now.
I have my cycle reverse of the DT as everyone recommends. I wonder if the little bit of light that actually comes in the basement window will hinder the dark side, LOL. I was going to wrap the container in some foam insulation to prevent the condensation I'm getting now. That should block out most of the light.

I used 1" pipe for my cross tube.
To cut the slot I use a rotozip. The bits are 0.125" in diameter so it makes a perfect slot in one pass. I made a jig with a little 2x4 and 1x4 and clamped the pipe to the 2x4. One straight pass and done.

I would just cover them up just a little, you dont have to got crazy. Maybe you can spray paint the outside of the container? Foam for insulation would both block the light and help keep heat in or out.

Nice work with the rotozip!!

[BluScrnOdeth]

I just changed those lights out what, two-3 days ago. The green is exploding. I'll try to get a pic up tonight when i get home from work.

[fppf]

Everything is foamed, more heat I keep in the less I need to pay for.

[srusso]

Originally Posted by BluScrnOdeth

I just changed those lights out what, two-3 days ago. The green is exploding. I'll try to get a pic up tonight when i get home from work.

Great to hear things are working well for you. Please post pictures as soon as you can. Also if you can post new ones each week before you clean your screen it will be helpful for others to see a screen maturing over a couple of months. thanks for posting!

[srusso]

Originally Posted by fppf

Everything is foamed, more heat I keep in the less I need to pay for.

Yeah, what type of foam are you using. I have been thinking about backing my tank with foam for a while now. Also want to completely cover my sump.

[fppf]

Depends on the area and if I need to get in there.
If its really irregular I and I never need to work on it I use spray foam in the can. For pipes, foam pipe insulation. For containers and flat places I found this aluminum backed self stick foam insulation for pipes. It is like 10-12" wide and sticks to the bins pretty well.

[Floyd R Turbo]

Originally Posted by g8gxp

how is everyone making the slit in the pvc pipe? i used a dremel and cut a 1/8 inch slit but i don't seem to be getting full coverage down the sheet. the water sheets well in the middle, but the sides seem to just get a bunch of little rivers of water. I've tried 4 or 5 different designs, the one i am using now is where i drilled little holes all the way across which seems to work, but the problem is that the algae is growing into the holes making it a pain to clean.

I know the slit is the right way, but i can't get the full coverage, is it because the pump isn't powerful enough? it's a maxijet 1200. or maybe it's that i'm using 1/2 inch pipe? too small diameter?

A 1/2" pipe restricts the flow significantly. You have to remember that the flow is proportional to the cross-sectional area, but that fluid dynamics states that a more restricted flow channel will contribute additional friction that will further restrict flow. You need 3/4" or larger pipe. You will see a dramatic increase in GPH from a 3/4" pipe versus 1/2" pipe from that pump.

[Floyd R Turbo]

Here's some math on pipe diameters:

1" inner diameter PVC pipe has a cross-sectional area of 0.785 square inches

3/4" pipe area is 0.442, or 56% of the area

1/2" pipe area is 0.196, or 44% of the area of a 3/4" pipe, and 25% of the area of a 1" pipe

This is just the cross sectional area. If the same pump were used on each of these pipes, and that pump had a flow rate at 0 ft head pressure (no deduction) or 1200 GPH, then the rate of flow would be:

1200 GPH * (231 cubic inches/gallon) * (1 hour / 3600 seconds) = 77 cubic inches/second of flow produced by powerhead

1": 77 cu in/sec / 0.785 sq in = 98 inches/sec

3/4": 77 / 0.442 = 174 in/s

1/2": 77/0.196 = 392 in/s (that's 32 feet/second, or 22 miles per hour)

There's no way you could get that flow rate from that pump, is just doesn't have the power to produce that much head pressure.

This same principle applies to many pumps, it's the reason why I only get 433 GPH at 4' head from my Mag 12 when it should be 800-1000 GPH. My return hose is 3/4" when it should be 1.5". This is a tank issue as well, because the bulkheads are 3/4" and 1", I guess manufacturers are assuming that everyone uses the 3/4" for the return pump and 1" for the drain. That means just about everyone out there is running pumps at probably 1/2 of their rated flow and they don't even know it. No wonder everyone needs powerheads in their display.

[CLINTOS]

Originally Posted by srusso

The lights should always be ~4 inches away. Closer and you will burn/bleach the algae. The lights become too strong in one spot.

makes sense

[srusso]

Once again Floyd, your contributions to this thread are priceless! Thank you for that last one!

[fppf]

Just my rule of thumb and opinion, take it for what its worth.

I don't use anything smaller then 1" on any of my plumbing for the tank.
If I'm doing feed and return lines for a filter I don't go smaller then 1 1/2".

I ran 2" for my feed and return because the run from the sump to the tank is over 30 feet with 12 feet of head. Yes, I have a large return pump.

Most times I go at least one size pipe larger for returns so I don't have any backup issues. For my main return I just ran 2" as well because I know I really did not need 2" for the feed.

The nice thing about having a feed that large and long, by time the water makes it to the tank any micro bubbles are long gone, LOL

[srusso]

http://reefcentral.com/forums/viewtopic.php?f=3&t=26

Here are hundreds of scrubber designs... I would post them all there but it would take me hours to do. Thank you goes to SantaMonica for building this list and all the people whose scrubbers appear there.

[BluScrnOdeth]

As promised. Here is what it looks like just 4 days after adding the warm 2700k lights. Not too bad,expected less cyno but its a lot better than what it was.

[srusso]

Great! Growth is much better then expected for 4 days! It helped that the screen was running for sometime before the lighting was changed. Please post your water tests if you can.