View Full Version : Macro Algae Reactor

07/14/2017, 04:01 PM
I just setup a reactor for my macro algae and was curious if anyone has been running one of these on a 24/7 schedule (basically never turning out the light)? If so are there drawbacks or advantages running like this. I had Cheato in my sump and was running the lights at night only so I've never tried leaving them on all the time.

07/14/2017, 04:46 PM
A number of people have done that successfully. It should be fine.

07/15/2017, 11:44 AM
Some general thoughts but no answers

Some macro algae need a dark period. A Google search on this may identify whether yours does. Strong water motion is very important for strong algal growh too.

An alga can photosynthesize whether it needs the carbon (carbohydrate) or not. There is no "off" switch. When it doesn't need all the carbohydrate, it exudes the excess. Does this extra photosynthesis act as uncontrolled carbon dosing? Probably. Could it be detrimental to coral? A possibility but I have not found studies that cover this topic. The two potential issues are excess bacterial growth in the system and toxicity of the carbohydrate because it stimulates the "wrong" bacteria to grow. These things happen in nature but I have not been successful finding scientific studies to understand the consequences in an aquarium. I have not even seen a good survey of aquarists to get at the issues, just anecdotal information.

One way to resolve this question is to measure alga mass increase per day under 12 hour and constant light conditions.

07/15/2017, 01:21 PM
Macros also need space; many use small algae turf scrubbers and/or refugia which are largely ineffective amounts. Exudates from some can be harmful and many are refractory,don't breakdown readily.

07/15/2017, 03:34 PM
Thanks for the feedback. This gives me a direction to do some research with some of the guys I work with. They are PhD Chemists and may be able to resolve some of these questions for me.

My algae growth system is separate from my tank and refugium so they won't be affected by the excess light. I tapped off of my 1 1/2" supply line which is fed by a 15000LPH pump to flow through the algae so it has plenty of flow. I guess if the chemists can't help then only time will give me the answer.

07/15/2017, 09:29 PM
I'd just watch the pH of the system. I don't have a good sense of how big the lit macro algae area will be in comparison with the tank, but photosynthesis will drive the pH up. I'm not sure it's possible for that to become a problem with most hobbyist setups, though.d