Planning a design for my 560 display

[wmilas]

I have a 560 gallon display. Along with the display I have a 175 gal sump (not totally ful) 65 gallon fuge/settlement tank, 40 gallon frag tank, and the external overflows are quite large.. they hold 15 gallons each. The total water volume of the system (after taking out sand and rocks) ends up being about 800 gallons.. at least thats what I calculate after years of adding calcium and alk two part. It seems pretty spot on.

So.. I have a monster ATB x-large cone skimmer. I do large carbon dosings via vinegar to keep the N&P in check. I've removed GFO 1+ year ago, although I do still run carbon. Top off is done via a kalk reactor. Although I can't really complain about the carbon dosing and the skimmer extraction, the more I experiment with the tank, the more I realize I'm completely underfeeding it. I can stimulate massive coral growth by feeding it "properly" but then I end up with an algal outbreak in my fuge and even worse, in my frag tank. I see very few signs of algae in my display because the tangs eat it all. I do see it on the glass, and I have gone through really horrid bouts of red/purple turf algae on my rocks. I'm aware the is most likely happening from phosphate leach after a large phosphate absorption/equalization.

So even though the skimmer works, I'm *seriously* considering building an algal scrubber.

The first thing I struggled with is cost. The materials I'm not worried about, its the consumables. Lets assume the standard parmeters that I've read here on the forums. Lets also start with the premise that I want to install the scrubber over the top of my sump which is not under my tank (I have a fish room). Sump's inner dimensions are 24" wide, 36" long (Its quite deep). I'll need 600 sq inches of screen, and 600 watts of light. I plan on building t5ho light boxes and sandwiching them between screens.

If I have 3 screen 22" long, 16(ish) inches high, with two light boxes between the 3 (ie screen, light, screen, light, screen) I yield 1056 sq inches, but because the ends are only half lit, that really yields 704 sq inches equivalent. That yields approx 13 bulbs per "light box" assuming I can actually construct something where I can mount them that close together. That's 312 watts per box, 724 watts total. Do these calculations make sense? More specifically, can you use these wattage calculations where the light box is throwing light 2 directions and not using a reflector?

I would use 3 separate pumps one for each screen as I don't want to drill my sump again. 3 pumps makes buying small submersibles easier. 22 inches per screen 35 gals per inch means 770 gallons per screen. Thats 3 mag 9.5's.

Total power consumption per day running pumps 24 hours and lights 18. 93x3x24 = 6696 + 26x24x18 = 11232 = 17928 watts or 17.928 kW per day. cost here in Illinois after taxes is 13 cents per kW. So thats $2.33 a day or $850 a year to run.

Its not quite that bad though. I currently do 50 gallon water changes once a week. I assume I'm going to alter that to once a month. I'll save 39 water changes or 9.75 cases of salt. $55 a case. Thats $536 savings right there. Skimmer pump draws 80 watts so I'll save another $91.

So it.. in theory, will cost me only $233 over what I currently pay... which isn't that bad. I can deal with that.

So my first questions are

1) Are my rough numbers correct?
2) Are the double sided light boxes feasible? Main reason I want to use them Is I can always construct a third with one more screen and wham, instant larger filter. The thing becomes modular.
3) The sink in the fishroom I'll be cleaning these in is 21"x21" and 12" deep. I want cleaning to be relatively easy. I'm assuming each spray bar will have 2 11x16 inch screens?

Thanks for your input.

[SantaMonica]

So even though the skimmer works

Yes it works; it's pulling out food.


I'll need 600 sq inches of screen, and 600 watts of light.

600 watts for high filtering. But you are not feeding much right now, so if you don't feed much more, you might get by with 300 watts. Of course, you could build for 600 watts, in 3 sections (3 screens of 200 watts each), and turn them on or off as needed.

But a more accurate guage is based on how much you will be feeding: Each cube of frozen food you feed per day needs 12 square inches of screen, with a light on both sides totaling 12 watts. Liquid coral food is more difficult to measure, so you'd have to dry it and pack it into a cube to see how much it is.


I plan on building t5ho light boxes and sandwiching them between screens.

For best results, have a light on both sides of each screen. You don't want one side of a screen to have dim light.


I currently do 50 gallon water changes once a week. I assume I'm going to alter that to once a month.

No need for them.


The sink in the fishroom I'll be cleaning these in is 21"x21" and 12" deep. I want cleaning to be relatively easy. I'm assuming each spray bar will have 2 11x16 inch screens?

If you have multiple setups, then each setup does not need to have the screen cut in half (although you still can); the split screen is really for people with just one setup, and they want to even out nutrient spikes. Since you want to be able to remove the pipe too for cleaning when needed, you can just keep the screen full-length, as long as it will fit into your sink. You can also make the screen less than the length of the bulbs, since the ends of the bulbs don't do anything, and for best filtering you don't want screen where there is dim light. So just make the screen 20" long.


Sump's inner dimensions are 24" wide, 36" long

Best way is just to show you what I would do. 24" is perfect for three 24" units side-by-side. Each unit would have one screen and a light on both sides, and would be about 7" thick, so three of them would only take up 21" of your 36" sump, and you could even add more later if you wanted, to get into high-feeding. Most important, each unit would be self-contained with it's own pump, for redundancy. This also allows you to shut off one or two units as needed to save power, or if you are feeding less, or experimenting. It's important than when you turn off units, you shut down the whole thing... flow and light... to the unit. You don't want to just turn off the light, because you only want algae growing in very bright light, not dim light. This is also why you want units with lights on both sides, so that one side is not in dim light.

So a 600 watt, three-unit setup would be 200 watts each, or 100 watts per side. This is 4 T5HO bulbs per side. T5HO bulbs need to be spaced no more than 2" apart for good filtering (1" apart for very high filtering). So at 2" apart, they would be 8" high, plus an extra inch on the top and bottom (no more, or they would be in dim light), for a total of 10" high. Since the screens are 20" long, each one would be 200 square inches. The three together would be 600 square inches, which put you at one watt per square inch, perfect.

[wmilas]

I'd rather not go into the pros and cons of skimmers. I'm here because I'm willing to admit that a scrubber leaves more food in the tank for corals.

As far as how much I'm feeding. I'm feeding what amounts to 8 cubes a day in food. Some days it can be a bit higher. Say 10 cubes. (Nori, liquid coral ect). I've doubled it and that's when I've seen faster growth. I can easily see myself feeding 20+ cubes a day.

Ok so you are recommending dedicated units where lights on both sides using reflectors. That would mean me either building them, or using something like the nova extreme 1120. the 1120 is 4 bulbs, 24"x7.5"x2.5" That would indeed coincide with your 7 inch thick assumption.

One problem I have is that I can't put the lights INSIDE my sump because when pumps turn off, the sump level climbs. If I put the lights on top, to stop the splashing I would need to extend the screens down into the sump. They wont have light. What are the ramifications? Are they simply wasted space, or would there be a negative aspect to having the screens bottoms with no light? It seems kind of silly for me to build something like the santa monica 100 only a 200 version when I don't really need a bottom as the whole sump can act as the bottom.

I can attach pictures of the sump if need be.

The last question is about transitioning the tank. I'd prefer not to shock my corals. I was thinking of installing one of the three units besides my skimmer and removing 1/3rd of the carbon I'm dosing into the tank. That, in theory, should add back 1/3rd of the P&N of the inorganic total that the skimmer is missing that's being used up as bacterial biomass (and then exported via skimming). Any input here?

Thanks for your time.

[SantaMonica]

The Nova lights would save you some work, although you will have to swap the bulbs.

You can do extended-length into the water below, but just keep the light real close to the screen. You'll probably want the extended part to be separate from the main part that you remove for cleaning.

As for transitioning, you are not doing anything now which would need it. If you were adding carbon instead of removing it, you'd want to do it slowly so the corals could get used to more UV light. Or if you were adding a skimmer, you'd want to do it slowly so the corals could get used to less food by increasing photosynthesis. And you aren't changing flow. All you are doing now is adding food to the system, which does not really need acclimation.

[wmilas]

Another option would be be for you to make a Santa Monica 200. Same dimensions as a 100 just taller.... and with the beefier lights. Interested? :)

[SantaMonica]

While it is possible, it would be a lot more work because it's not known what the dimensions of the box would need to be to match the lights. Plus, then you have drain tubes, which you said would seem wasteful in that sump. It would be very expensive and a long time to make just one; really a better idea would be several 100's, if you were going to go with the pre-build route. At least this way you'd get 3D scrubbing as it backed up in the box, which makes it as strong as a bigger screen without 3D.

[wmilas]

Btw if it matters I built a wood shell prototype to hold the current usa fixtures. I built the unit and screen per your specs Santa. (Bought a multi-tool to rough up the screen which saved ALOT of time) The flow is a little over the 35 gph.. closer to 40. Screen is 1 to 1.25 inch away from the light source on both sides. Screen is 21.5" long, and I'm guessing the concentrated light spread is about 10" and not the 8 " you theoretically drew up so I have slightly more than the 200 sq inches.

I stopped carbon dosing last night and brought the prototype unit online. I stopped carbon filtration also. I added a bit of iron to hopefully kick start growth. Skimmer is still running until I see growth then I'll take it off line. If it functions how I hope it will I'll build another unit out of plexi (I do have plexi screen on this unit stop the splashing) and replace this one with a plexi version. I'll then take stock of the situation and see if I need to build a third.

I'm interested to see if this works.

[180rftank]

I am in the process of puting together a ATS for a 500gal myself, so I feel your pain! The cost of the bulbs every three months is hard to swollow, but think about the time and energy one must put forward on doing water changes on a 500gal reef tank. I'll stick with 3 SM scrubbers!

[wmilas]

The cost isn't that bad. I ordered them from 1000bulbs.com. They are pretty cheap. Its the electricity draw that's the killer. On the other hand the amount I'm saving by offsetting the fuge lights, the skimmer pump, the carbon pump, and the VSV doser along with reduced salt usage will make up for a lot of it. I'm hoping to get away with 2 200 sq inch units, but I'll make the third if need be.

I'm going to order the acrylic to make the first one next week. Well, make the first REAL one. My wood prototype seems to be chugging away just fine. After 36 hours I'm not seeing a diatom brown on it yet, but there are a few tiny pieces of green hair algae stuck to the screen. That's gotta be a good sign.

[tangwrangler]

Watching this thread...Keep us posted.

[wmilas]

I probably should take some pictures.. but its xmas eve.. Isn't going to happen :(

[Vannpytt]

How much flow are you putting over this screen?

[wmilas]

Mag 9. I plumbed it with 1 inch spa flex and 1 inch elbows to 1 inch tube. Vertical rise is only about 3 feet so I'm guessing 800+ gph. So over 35+ gph.

[Vannpytt]

And how wide is the slot? (is this for each?) I use almost 2k gph for my 180gallon.

[wmilas]

I only have one of the 3 units running. Slot is 22" long, probably about 1/8" wide.. maybe less. Its the thickness of the kerf of my blade. The screen fits snugly into it.

[wmilas]

Ok 4th day.. and some problems. My nova extreme fixtures are 2.5 inches apart from the front of the glass. That means its 1.25" from front of the fixture to the screen. From the lights in the fixtures its about 2" to the screen.

I'm getting a brown diatom/slime growth above the photo line and below the photo line. Ie above the fixture going to the slot and below the fixture. Its growing in the light "spill" area. I'm getting NO growth of anything directly in front of the lights. Is the light too strong? This doesn't make sense since I don't think it could be too strong, and I'm using approx the same distances as the SM 100.

I took my skimmer offline day 3 BTW. I'm running absolutely no filtering of any kind now except for the scrubber. My tank before the transition was low nutrients.. nitrate and phosphate tested 0. I ma getting green hair algae growth like mad though in my frag grow out tank where there are no herbivores to mow it down so I SHOULD have some kind of growth on the screen.

Santa, also, where do you source your combo bulkhead/barb that you use on your pipe?

After doing some modeling I've decided I'm pretty much just going to build 3 SM100's scaled up to SM200's when I do it "for real". I'll use 1" plumbing though and the nova extreme fixtures.. All my designs I come up with aren't as slick as yours.

I'm telling you, if you made SM 200's you'd sell em. :)

[Vannpytt]

Need more flow...

[wmilas]

850 gallons of flow for a 22 inch slot? (900 gph pump but I'm losing 50 gph in head pressure) that's 35+ gallons a minute per inch.. I measured the flow myself to confirm it. Water is cascading in a torrent down the whole screen with no dry spots anywhere. Even the sides are completely wet. I'm thinking its not the flow.

[Vannpytt]

I thought the same thing. I have widened the slot quite a bit with my dremel to something like 4mm, and only after that did I get really green growth. I had yellow emptyspot screens up untill that for many months.

Try roughen up the screens more?

[wmilas]

Hum. Interesting. I'm just perplexed why there is NO growth right in the middle of the screen, but lots of scum growth at the top and bottom. I'd understand if there was less growth, but the center of the screen is pristine white. I'm considering unplugging half the lights on each side to see what happens. Does your screen move around lose in the slot or is it a snug fit? also, do you push your screen "all the way up" into the slot or is it just barely in the slot?

Of and I did use a multi-tool and a hole-saw to roughen the screen up to cactus proportions before I put it on.

[Vannpytt]

Growth over and under proves my point. The algae gets "burned" and won't grow, however, you can see really nice growth where the light/flow area is more in favour of flow than light.

Seriously, save yourself some time. Buy stronger pumps. I wasted 3 months with low flow.

[wmilas]

Ok. So Santa recommends a Eheim 1262 for a 22" slot in a 3/4" pipe. (thats what he's using for his SM 100) Thats 900 gph flow. I'm using a 1" pipe and a mag 9 (again 900 gph flow). I'm not doubting you or arguing, just trying to figure out how to approach this. Can I get more than 900 gph out of the 22" slot in the tube? I'm thinking it might already be pressurized? If so what pump do you recommend?

[wmilas]

I decided I'm going to cut another tube tonight and widen out the slot a bunch. I'll probably cut 2 more tubes one 2x the thickness it is now and one 3x so I can see what the water flow is like with each. If its too wide for the flow it will sheet in one place I think and leave one side dry.

[Vannpytt]

I'm currently using a 25mm (1inch) pipe with a 4mm slot. It's 32 inches wide. This is fuled by the largest Tunze Master electronics after head loss aprox 6,5k lph. (it's rated 8,3k lph without loss). Mine is fed with the return of 2x32mm (1,5 inch) durso pipes.

In my experience I would go even bigger for flow. Offcourse you can reduce light, but that is also reducing the potential of the scrubber. Honestly, it's a totaly different world from my old Deltec HLP 5250 (5,3k lph without loss) to this one, and I could even go larger. It works as intended, and let me tell you this. You will get growth, yellow in a week or so, and you will be "happy" but for me, again, the difference in yellow and green (without adding iron) is just massive. I had a 180gallon DT full of algae and dying SPS. After 2 weeks the only algae growing is the ones on my scrubber and my SPS are alot more happy. I also added some GAC to remove possible toxins from the dying SPS and this stopped my RTN almost instantly. Algae did not kill my SPS thought, but the "debris" of large accumulated biomass through cycling with the nonworking (not enought flow) scrubber.

Go for a 1200 gph pump at least, and even 1500 gph. You will be happier.

[SantaMonica]

Sounds like you are not turning your lights off for 6 hours.

I got the barbs from:
http://www.dripworksusa.com/store/barbed.php
P34INBA-3/4in PVC Insert x 3/4in Barb

[wmilas]

I just re-cut the slot to be 4 mm. It was closer to 2.5 to 3 mm. Probably 2.5 mm. So its like 5/32 inch thick now (little bit larger than 1/8). I had assumed it was 1/8th before but i realized I had a think kerf blade in.

Santa: Thanks for the source info. My lights are off exactly 6 hours a day atm. Have been that way since start up.

I'm thinking it was a flow issue. Flow seems to be marginally stronger now. But not double or anything. I cut another test slot 6 mm wide but it was spraying water everywhere. The 6mm slot did flow more water though... just all over the place.

Santa: Think I should turn off 2 lights per side till I get algae growth then turn them back on to see what it does? Maybe reduce the photo-period to 16 instead of 18 hours?

I took a short video of the flow. Please excuse the sloppy wood scrubber.. its just a prototype for me to play with the parameters.

http://www.youtube.com/watch?v=SUGHp06eRGQ

[Vannpytt]

Hard to say if it's enought, but I do still think you'll find that you need even more.

[SantaMonica]

I'd say just let it grow and see what happens. The first days are always variable. If it's going to fill in, it will fill in. If you are going to reduce light, always shorten the period instead of removing bulbs; you always want strong light when it is on.

[wmilas]

I'm going to shorten the photperiod to 16 hours. I ordered a mag 18 which should be stupid flow. I'll see what happens :) On the plus side the over and under part are getting nice and black and slimey :)

[Vannpytt]

Beg to differ. The less photoperiod won't make it better overall. You want the scrubber to be optimal, and for that to happen you will need stronger flow. If the flow is "too strong" widen the slot to let it flow freely

[wmilas]

Ok putting the photo period back to 18 hours. I realized I had an extra mag 18 sitting around here after I ordered one. Doh. I'll be hooking it up this morning an probably re-cutting the slot again. I looked closely at the flow for 5 minutes. You are right, its not enough. After widening the slot day before yesterday, today there is growth in the center, but its still yellow. Needs more flow.

[wmilas]

I'm also noticing some curious things.

1) My ph is rising. This is odd. Its at 8.32 now. I used to hold stable at 8.18 to 8.2 I had undetectable nitrates and phosphates with heavy carbon dosing. My sump room is a sealed room which I regularly turn over the air in with outside air via an air exchanger so that I would not build up co2. In theory I was pushing a lot of oxygen into the water with the skimmer. The algal scrubber seems to be pushing more o2 in, or taking out "stuff" that was causing acidity. With more organic mater in the water breaking down and causing acidity, I would have thought my ph was going to drop.

2) The slime growing is very dark. Its a very dark brown with a hint of red. Looks like a mix of diatoms and cyano almost, but it seems like neither. I would have thought I would have had bright green algae. I had too few nutrients in my tank and I was bleaching corals.

3) My corals are recovering color much faster than I thought they would. My red planet went from pink to more red than pink in less than a week.

[wmilas]

Hooked up Mag 18. Slightly more flow, but not double. I hooked a watt meter up to the mag 9.5 and the mag 18. 9.5 was reading 80 watts, 18 is reading 98 watts. Pumps pull less wattage when their flow is restricted. the mag 9.5 is pretty much unrestricted, the 18 is restricted a lot at this point. Later today I'll re-cut the slot by 1 mm and see what happens.

[wmilas]

I've been looking for an excuse to order a set of spiral up cut bits, so I just ordered a bunch of em. Should have them in a few days so I can make exact, repeatable varying length cuts.

[Vannpytt]

"I told you so" ;)

Glad it works out for you. The 2x is not needed, you just need alot more than 35 gpi to make it grow green with the powerlights beeing so close. I would know, I have 3x 39w T5HO on each side. It takes about 6k lph to make it grow even. (My slot is, as I said, alot wider), but the general idea is the same as SM always says. Don't know why he's so blunt about it now. 35gph is only a minimum ime. You want as much as the screen can hold +2.

I had a nice talk with Dr. Walter Adey regarding calcification, coral growth, algae and related issues. There is no question in my mind that this is correct, or I would have given up a long time ago, considering I'm facing some problems with my own scrubber, but it's finally looking good and doing what I was setting out to. My issue is that there is noone else running as powerfull scrubber as I made, so I'm plowing new terrain. If what SM say's as guidelines, my scrubber is standalone filtration for a 300 gallon heavy stocked, but most scrubbers I see for these systems use the 24" slots, and I'm using the wider and less deep screen wich should be alot more efficient, but also alot more expensive and larger.

pH will increase as the Co2 gets ripped out of the wather and so you don't want to add O2 to your system. You want as much carbon as possible. This is the reason everyone (and I'm not just speaking about scrubber tanks) with some withs looks at these parameters first:

1st Magnesium - Hardly ever depleted, but has to be maintained to keep the balance. High 1450-1550.
2nd dKH/pH (Alkalinity) - This will be a source for coral calcification if there is not enought carbon from the air available (The stronger the scrubber, the more of an issue) Keep this up around 10 with KH buffer or Natron/Bakingsoda/BiCarbonate. Dose straight into tank, but wait atleast 6 hours before doing kalkwasser or another calcium addition.
3rd Calcium - Really explains itself. Keep it up at steady levels for maximum growth on corals, coraline etc, but be aware that without the proper trinity in balance (Mag/Alk/Cal) you won't grow at optimum levels.

I do my own Magnesium supplement though Magnesium Chloride, and it's basically in the start untill things are going steady.

The scrubber will add wastly more o2 than a skimmer.

[SantaMonica]

In theory I was pushing a lot of oxygen into the water with the skimmer. The algal scrubber seems to be pushing more o2 in, or taking out "stuff" that was causing acidity. With more organic mater in the water breaking down and causing acidity, I would have thought my ph was going to drop.

It removes CO2 (algae eats it), and adds O2 (algae makes it).



I had too few nutrients in my tank and I was bleaching corals.

That won't happen with a scrubber, because as the nutrients become lower, the algae growth stops. It's self-controlling.



My corals are recovering color much faster than I thought they would.

Because now they have vitamins, proteins and amino acids (all DOC) in water, as well as food particles.

[wmilas]

First cleaning last Sat. Pretty much just a coating of brown sludge. Not very thick. Slightly thinner in the lighted area (I know more flow). The brown sludge, when it dries, turns green. Very odd. Scraped it off and put screen back in. Growth continues and tonight more sludge is growing on it. I notice the same sludge in my tanks growing on the back wall of my tank, and on the non-light exposed areas on my rock work.

My bits came in. Going to experiment with different slot sizes. I'm going to draw out the SM 200 and order the black acrylic sometime this week. Solvents should be here tomorrow or Wed. I have plenty of 1/4" clear acrylic on hand.

[wmilas]

Posting a progress update.

Screen is growing some green but still mostly that brown/purplish stuff. Center of screen directly in front of the lights is still yellowish. I've started dosing more iron which seems to be causing more green growth. The black acrylic just showed up yesterday so hopefully this weekend I can start on the sm200 build. I'll run the first sm200 side by side with the prototype, and if it works out well, I'll take the prototype down and build another sm200.

As a side note my alk consumption has spiked. I attribute this two a few factors. 1) the screubber. 2) Faster coral growth due to more feeding. 3) Faster coral growth due to to higher ph. 4) More coraline growth.

[Vannpytt]

Adey, like everyone on this forum running successfull scrubbers, have experienced that alk will be consumed due to very low Co2 in the water. This as a substitute for coral/algae photosynthesis and needs to be dosed and kept at high end values.

[SantaMonica]

Photosynthesis is still occurring, of course, it's just getting it's carbon more from bicarbonate than CO2. This is how the pH goes up.

[wmilas]

Ok so I still haven't built the first SM 200 besides the prototype. I hope to start on it this week. Anyways, I'm still a bit miffed with the prototype as far as algal growth. It probably is a flow issue but it's still pissing me off. I'm getting bands of dark green :slime" growth at the top and bottom of the screen, and yellow slime in the middle. Its fiberous slime, but still slime. There is a little purple slime mixed in. When its scraped off it smells sickly sweet. I'm getting no algal green ling hair growth at all. However, my frag tank, which has a 15k 175 watt MH with no herbivores in it is growing hair algae and bubble algae like no tomorrow.

I'm getting about 1 cup of slime per side of the 24 inch screen.

I'm worried that I'm going to build the prototype and have too much light on each side. To recap I'll be using 1" plumbing and I'll have about 45 gph per inch.

[wmilas]

Oh also, I'm dosing iron, but it doesn't seem to be helping. The scrubber (or other algal growth in the system) seems to be doing something though ask alk uptake continues to increase.

[SantaMonica]

Just needs to grow more.

[wmilas]

Could you expand on that? Do I let it grow more before cleaning, or just more time to mature?

[SantaMonica]

More weekly cycles.