View Full Version : algae film and sedimentation filter-?

07/15/2016, 01:34 PM
Hereís the setup Iím working on-

-120 gallon dark tank for NPS no substrate moderate flow
-75 gallon brightly illuminated high flow algal film snail scrubber- stacked panes of acrylic growing surface and Stomatella-diminant grazers- no substrate
-75 gallon very slow flow dark settling filter

The purpose of this setup is to culture NPS organisms. Imagine, to make this idea clearer, that the Caulerpa in a Miracle Mud filter was continually ground up and returned to the system as food, along with the digestive enzymes and trochophore larvae that Stomatella put out.

Iíll have to determine the amount of ďsinkĒ for phosphate in the settling filter, but I suspect phosphate will accumulate; so will probably use KNO3 or NaNO3 for level of 10PPM, aim for phosphate thatís nearly detectable, and dose iron and silica and iodine. If phosphate doesnít accumulate would use maybe Florida Aqua Farms additive for NO3 and Phos. Or maybe some phospholipid-rich food for phosphate and use a phosphate remover, although i hate to do that. All the nutrients will be dosed weekly into the top off water.

Setting up test tanks, the problem I get is that it is surprisingly difficult to maintain a rapidly growing algal film and continued pearling. Any deficiencies and the film crashes, along with the micro grazers (ciliates, small nematodes especially). If N or P gets too high, the diatoms overgrow the surface and flocs break off. Probably I can handle this by carefully regulating the dosing.

The most difficult problem, though, has been alkalinity- which climbs (due to denitrification I assume) and pH that rises too high. When I dose vinegar the film thins and crashes, or there is a bacterial bloom that wonít clear (maybe not a problem when the sponges start growing but in general liquid carbon dosing has not worked well for algal films).

So- maybe a CO2 reactor into the algal film tank with a target of pH 8.1?

Michael Hoaster
07/15/2016, 05:50 PM
This sounds like quite a challenge! I know very little about NPS organisms, other than they are hard to keep. I'd like to know more, so I have some questions:

What non-photosyntetic animals do you plan to keep?
The snail poo and larvae are the food? The only food?
The purpose is to culture NPS, so this is not a display? More of a frag farm? Experiment?
Is the algal film/snail scrubber your own idea, or a proven method of NPS culture? How did you arrive at this feeding method?

It's pretty fascinating stuff! I have one non-photosynthetic gorgonian and several sponges, so you definitely piqued my interest. Can't wait to hear more!

The problem of maintaining high algal growth might be helped with a few fish, otherwise you have to dose everything. Plus fish are prettier than chemicals. I also got bacterial blooms and cyanobacteria, dosing vinegar early in my tank's life. I think it's safer in mature tanks. I use CO2 in my seagrass/macro tank to great effect.

07/15/2016, 06:32 PM
Thanks for the reply. Really, the point of the setup is to explore a reef system based on primary production and recycling, rather than an system based on feeding a lot and cleaning a lot. I’m looking to close the loop except for minimal inputs needed to grow organisms.

One point I didn’t make in the first post- almost all of the carbon and nitrogen fixed in the algal film tank ends up in the settling filter, where it will be recycled to ammonia and CO2. So the system will accumulate carbon- perhaps no dosing will be needed after the system equilibrates...

Michael Hoaster
07/16/2016, 01:16 PM
Sounds great! Can you answer any of my questions?