I would like to put down some rambling thoughts and hopefully get some good input to help me finalize my ATS design. Please comment on any parts of this thread.
I feed my 130 gallon tank very heavily for non-photosynthetic corals and other filter feeders. For about 2 years, I have been running only a 55 gallon sump with a deep sand bed and the rest of the volume is filled with an extra porous coral rubble (not lit). The bacteria keeps the nitrates at a reasonable level but phosphates are not good enough. This is becoming more apparent as the volume of feeding increases. Additionally, the sump out competed with the Algal Turf Scrubber (ATS) so it stopped producing algae for export. I think that the lighting was also just a little inadequate.
I plan on disconnecting the sump and go back to my tried and true dump bucket style Algal Turf Scrubber. A lot of people like other designs for some very good reasons but I like this one for me.
The dump bucket was a lot harder to design and fabricate but I like the splash that it produces. The turbulence inside the tipping tray prevents algae from matting for a much longer period of time so I don't have to be as fastidious about harvesting. When it is harvest time, the balance point changes and the tray stops tipping, coming to rest in the down position. Testing shows that the constantly changing water surface, causes a flashing effect that concentrates light. That and the turbulence greatly adds to the efficiency of the scrubber even though it is a one sided design. The two designs run neck and neck on efficiency so it just comes down to personal preference as I see it.
Having made that decision, I am trying to decide on the lighting for my ATS.
The screen is 42 inches by 6 inches which is 252 square inches. I guess that I need about 250 watts of light. What do you guys and gals think?
I'm just not ready to go to LEDs yet so I am going to whip something together before I go pro. I need to find out how many lumens I need first and I am a long way from doing the research that I need to do.
My first ATS back in the yearly 90's used a 300 watt halogen lamp. I lost a gallon of water per day to evaporation in my old 55 gallon tank but the tank temperature actually went down.
My next tank was a 130. I bought an Icecap ballast that I used to run 4 old styled VHOs. I still have the set up but I don't want to have to buy a set of the bulbs and pay for shipping or buy them at the local store at pull price. This is more important if I am really supposed to change the lights every 3 months. I never did and had great results. I could change to T5's but I would still have the same issues.
Since I have lots of room to work with, I thought about using 4 55 watt compact florescent bulbs that I could get at Home Depot. They aren't real cheap unless they are on sale and that might not be in the right K range. I could also buy the cheap 23 watt lamps in value packs. Say 12 in an array. That could be more hassle but on the other hand; I could buy a pack and change out a 3rd every month. That way I wouldn't get big fluctuation in light out put. With more lights, I could turn on some fraction at a time to tune or scale the amount of light that I actually need.
Some people don't like the spiral design, thinking that the light isn't dispersed the very well. Again the up side is that I can get them at a moments notice at a good price. Of course, what ever design I end up with will have outdoor sockets or end caps and a good reflector.
What are your thoughts on these subjects? Your input would be greatly appreciated.