120 liters, 1 meter high HQI high powered scrubber

[AngeleToR]

Dear all,

My name is Angel, I'm a spanish saltwater aquarist and have been running a 650 l aquarium with ONLY algae scrubbing for one year. Recently I moved from town and I am setting the whole thing up and I'm trying to improve an already working design (very BIG thanks for SantaMonica for sharing this with the world) to make it even better and easier to maintain.

My setup will be a 120 liters trash bin (squared one) with 4 nets hanging from top of every wall where one of the tank drains will be overflowing to. I plan to add a recirculation pump also to reach the 6000 l/h I calculated are needed for the lineal amount of one sided mesh I will have to cover. The bin is about 50cm every side, and as I have just finisished a new led fixture for the main tank, I have a great 250W HQI electronic fixture. My plan was to use this to drive a 250W warm white lamp to get those 33000 lumens 360º all around it promises and grow the most algae ever in my scrubbing history.

The problem is, of course, the heat. I've think of a system to drive heat away of the circulating water in a sealed acrylic container, the following way:

One 9 centimeters acrylic pipe where ligthing will be, placed inside a second bigger 20 centimeters of diameter acrylic pipe, which will be the exhaust pipe. I put a 9cm blower on top of the small pipe, blowing air in (or out, whatever is best) through the small pipe. Both pipes are glued in the base to a round acrylic sheet to make the setup water proof. That way, the air enters and exit from the top (I would redirect the in and out to avoid recirculating hot air). The inner pipe will be drilled in the base for the air going down to have some place to exit the inner tube and exit trough the outer.

I hope to have explained it well enough. Initially I though this system for 55W PL lighting. Those get hot when they have no air circulation and get to deform the acrylic over time, so this new 'device' will allow me to hold several of those in the exhaust outer tube near the nets. But if I where able to run the HQI it will be cheaper in lamps, brighter in lumens and easier to maintain, with less hours of lighting needed, and I do have all the parts already...

So the question is, will I be able, someway, to cool down enough a 9 centimeter acrylic pipe with a 250W HQI inside just forcing air through it??? Anyone ever tried something like this??? The HQI metalic casing gets as hot as 90 Celsius degrees, but the lamp itselfs gets over 130 celsius degrees, wich will melt the acrylic for sure. There would be as little as 2-3 centimeters between lamp and acrylic, but I've seen 50W fans able to move HUGE amounts of air relatively silently.

I wil make some schema to post it and help you understand the idea, so we can find the best design possible. SantaMonica, if you find this setup interesting you can use for your own designs, it will be my pleasure if it where that good.

Best regards from Spain!!!

Angel

[SantaMonica]

Welcome.

Before deciding, take a look at the new size guidelines. Scrubbers are now sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons you have. So...

An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or
10 pinches of flake food per day (2-sided screen), or
5 pinches of flake food per day (1-sided screen), or
10 square inches (60 sq cm) of nori per day (2-sided screen), or
5 square inches (30 sq cm) of nori per day (1-sided screen), or
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

High-wattage technique: Double the wattage, and cut the hours in half (to 9 per day). This will get brown screens to grow green much faster. Thus the example above would be 12 watts on each side, for a total of 24 watts, but for only 9 hours per day. If growth starts to turn YELLOW, then increase the flow, or add iron, or reduce the number of hours. And since the bulbs are operating for 9 hours instead of 18, they will last 6 months instead of 3 months.

[AngeleToR]

Hi Santa Monica,

Thanks for the quick reply and the directions. I had already read all your section about the new sizing guidelines, and my setup is oversized for my live stock right now, but I want to be always on the safe side, and I do want too to deactivate the skimmer once the scrubber starts working 100%.

The main advantages of my new design over my two previous ones (those were based on your first designs at once, with small mods to fit my needs) is mostly the mesh surface, that will be doubled thanks to the vertical setup of my bin, and that I expect it to be sealed with no evaporation and no leaking into the lights compartment (that's my main concern, as lights will be so near the bin sides and will get splashed for sure.

My problem right now is how to take the amount of heat generated by a 250W HQI bulb away quick enough as to be able to enclose it in a 9 cm acrylic pipe (2,5cm / 1 inch of separation between bulb and tube) and don't end up with a melted acrylic mess. Anyone ever tried something like this??? And if so, what volume of air has to be forced into the setup to keep the acrylic in safe temps???

I know this is not directly related with algae growing, it's more an experiment to be able to fit the most powerful lighting possible in the most reduced space, and HQI in this case outperforms led lighting by 2x, according to my calculus...

Best regards, Angel