New Freshwater Scrubber

I have been lurking around for a few days and finally decided to join. Great site by the way.

I have a small (1775 gallon) central wet/dry central system for my breeding tanks. I enjoy keeping and breeding Cichlids from Lake Tanganyika in eastern Africa. Has anyone here made a scrubber similar to my requirements? After doing a some research I have come up with an idea for a scrubber. As per the standard recomendation I need 1775 square inches of screen material. I am planning on using five gallon buckets as I don't have enough area in my sumps. I can make my screen 11-3/4" wide since the standard five gallon bucket is 12" diameter so that means I need 12'-8" total length. Due to height limitations I will need three screens 11-3/4"x51" with their own bucket. With a width of 11-3/4" I would need a flow of 412 GPH per screen. The top of the screen is 6' above the sump so I have selected a Via-Aqua 3300 pump for each screen. Since the screens are over four feet in length I was thinking of using four 26 watt 2700 K compact flourescent bulbs (two on each side) on each screen. Thoughts for improvement.

I am currently doing 50% weekly water changes which is about 890 gallons. So take 890 gallons weekly multiplied by fifty-two weeks and that comes to 46,150 gallons of water a year. It costs me with the additives that I use about $1500 a year. From what I have read on this board my PH 8.6 to 8.8 shouldn't go down over time using a algae scrubber like it does not using one. I use baking soda to raise the PH as it is only 7.0 out of the tap. I can't imagine the scrubber lowering my general hardness over time. It is nothing but magnesium ie epsom salt. The Seachem Lake Cichlid Salts are a little more complicated. According to their literature it adds 10 mg/l calcium, 35mg/l magnesium, 30 mg/potassium and 65 mg/l salt. If I was able to greatly reduce water changes or do away with them completely I would need to replenish the calcium and potassium. Maybe some of your saltwater enthusiasts can help me with that.

Questions?

Is it better to cross-cut the water distribution pipe at the top of the screen?

What are the chances of being able to eliminate water changes?

You don't want to use buckets. Make a multi-screen setup, in an old tank, like this:

http://www.radio-media.com/fish/MultiScreen.jpg


Make the total of all the screen about 2000 sq in. Use at least 1000 watts of T5HO (along the top and sides) for a normal power scrubber; Use 2000 watts for high power.

If the purpose of the waterchanges is to remove excess Inorganic Nitrate and Inorganic Phosphate, then yes the scrubber will eliminate the changes.

The scrubber will not remove much (if any) noticeable alk. It does use alk, but not much.

Yes cross cut; will allow you to use more flow.

And use two layers of screen, VERY VERY roughed up so it feels like a cactus.

Thanks for the quick reply Santa Monica! Using the old tank multiple screen setup how do you make the screens easy to detatch for weekly cleaning? My central sumps are not complete so I am thinking of doing all three of the 40 breeders as algae turf scrubbers to get the flow I want to achieve. A flow of 7750 GPH will turn my breeding tanks over four to five times per hour. Each of the three sumps will get 2585 GPH so 2585/35=74" linear /17.5" width of tank = 4.2 (5) 17-1/2"x12" screens per sump. This would total about 3,000 inches of screen. Try to imagine three 40 gallon breeders sitting side by side with six one inch inlets in a plexiglass cover on the top of each tank. The end pointing out has three 2" bulkheads drilled as low as possible which runs into a 4" pvc header that feeds the 7750 gph inline pump that pumps the water back to the tanks. As for lighting could I make anything more cost effective like compact flourescents work. 2000 watts would require a 20 amp breaker just for them.

Using SM's scheme you can either make the screens detach from their slots via bendable, springy, frames or you can split the the fittings on each end of the horizontal pipe so the pipes just lift out sort of like separating a clam's shells if there was no hinge. This is because you have little actual pressure feeding the horizontal pipes. (It's all about flow not pressure) That way you can lift out the cross pipes with screen attached and service them.

I would also point out you might want two pumps that source water to diagonal corners to get better flow distribution.

Certainly ditch the 5 gallon pails as you would be throwing away half the light in your multi-screen application.

As I stated in my revised post my system will consist of three 40 gallon breeders used as sumps. I already have a 4" pvc and a 3" feeding the sump via gravity. Two of the sumps have six 1" fittings mounted in an acrylic top and the other one has four 1" fittings mounted the same way. I have it designed for approximately 500 GPH to flow through each 1" opening which totals 8000 GPH but the pump returning the water back to the tanks only flows 7750 GPH at 10' which is what I have calculated for the system loss. The front of the sumps have 2" bulkheads mounted as low as possible which feeds a 4" header that feeds the pump. With all that being said what I am thinking now is piping the inside of the sumps to make an algae scrubber in lieu of the wet/dry that I have been planning. I am thinking of taking all six of the 1" openings and plunbing them together to make five screen drops. With them all being tied together the header should distribute the water fairly evenly. The sumps are 18" wide which means that I have 17-1/2" x 5= 87.5" to work with. 87" x 35 GPH per inch = 3062 GPH for the first two sumps(the sump was designed for 3000 GPH so we will be slightly under the recomended 35 GPH per linear inch. The last sump is also 18" wide but has only four 1" openings in the acrylic cover. If I plumb these together as described previously with three screens that would give 38 GPH over each linear inch of screen. I was thinking since the top is acrylic and the tank is glass I could use compact flourescent lights on top of the acrylic cover and compact flourescent lights shining in horizontally from the front and on both sides.

Is this feasible or am I way off base so far?

The 1000 or 2000 total watts is for CFL. So it is already as economical as it can be. 1000 will work fine, but 500 would be experimental.

Your flow seems good.

Forgot to mention, you'd certainly want a separate pump on each scrubber, for redundancy and ease of cleaning.

clayn; Your plan seems pretty sound to me. I'm not seeing any red flags.

Thank you both for your help.

Since the system is gravity I am having truble understanding the purpose of the recirculation pumps in each tank. Is it simply redundancy? If I do need them how do I size them?

I thought SM was suggesting T5HO's earlier. So sixteen 23 watt R-40 Reflector CFL (125 watt incandescent equivalent) would be good. Should I add something reflective on the dark end of the tank ie the end of the tank with no lights shining in? Since I have plumbing over the acrylic cover I can't get every light exactly where I want it over the sump but I think that it will be ok.

Quote:

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Originally Posted by clayn

Since the system is gravity I am having truble understanding the purpose of the recirculation pumps in each tank. Is it simply redundancy? If I do need them how do I size them?

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No, you need no pumps as long as your overflows move enough water.
If you need more flow then just recirc some of the water out of the sump thru a particular screen.

Quote:

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Originally Posted by clayn

I thought SM was suggesting T5HO's earlier. So sixteen 23 watt R-40 Reflector CFL (125 watt incandescent equivalent) would be good. Should I add something reflective on the dark end of the tank ie the end of the tank with no lights shining in? Since I have plumbing over the acrylic cover I can't get every light exactly where I want it over the sump but I think that it will be ok.

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I'm not clear on the lighting scheme you guys are talking about. I use LEDs. All I can add is a reflector probably is not worth the hassle and maintenance. It won't reflect much light unless it is highly polished aluminum, which a few splatters, will completely destroy...