Keeping Long Island Sound tidal zone flora and fauna. Before moving to CT, I owned 7 marine aquariums housing fish, soft coral and LPS. About 600 gallons of water in total. I was bitten badly by the reef aquarium bug. Ten years after moving, I decided to set up a salt water aquarium to keep local flora and fauna. I thought I would start with tidal zone creatures figuring they might not have temperature needs that would require a chiller.
The set up. Forty gallon breeder tank, glass top, two T5 lamps, small powerhead for circulation, Sterilite sump, DIY GAC reactor, DIY skimmer, 165 gallon per hour circulation from tank to sump, two 120 watt equivalent 5000 K CFL bulbs over the sump, local macro in sump. There is a two inch silica sand bed and a collection of granite stones.
Stocking history. Started with local macro algae on rock. Could not keep it alive. Who can't grow algae?!? Snails, hermit crabs and Asian Shore crabs went in next followed by grass shrimp. Continued to attempt keeping macro algae. Then came the Killifish and Pipefish. Moved inverts to the sump because the fish were harassing them. Here is a link to a short aquarium video taken around day 120.
https://m.youtube.com/watch?v=n1TzPQzFS2Y
Here is the nitrate and phosphate chemistry and stocking history.
How's it going now. Fish are growing. Killifish are mating. Pipefish are eating larger food and learning to keep it away from the other fish. Macro alga is finally growing well. It stopped dying after fish were introduced and now growing vigorously. Undetectable nitrate and phosphate levels.
Surprises or things I learned along the way. Even stocking an aquarium with everything straight from the Sound, the tank went through all the phases new salt water tanks go through. I never figured out why macro algae, including hair algae, wouldn't grow until fish were added and nutrient levels became undectable.
Nitrates did not start to accumulate until snalis and crabs were in the tank. No amount of dead macro algae resulted in detectable nitrate. Phosphate started accumulating with onset of regular feeding. Nitrate level went to undetectable even though there was no live rock or algae. The sand bed from the beach was apparently enough to set up denitrification. This not surprising in light of the work reported by Toonen's on substrates and plenums. In this studies nitrates did not accumulate as fast as ammonia was consumed, indicating that even shallow sand beds are acceptable environments for denitrifying bacteria.
http://www.advancedaquarist.com/2005/6/aafeature
Cyanobacteria started in earnest after the fish went in, and in this set up, it has resisted all standard "remedies" to date. I did not try Chemiclean, or Dr. Tim's yet. The use of GAC seemed to have no impact on cyanobacteria growth and GFO while it brought phosphates down to an undetectable level, had no impact on cyanobacteria growth. Macro algae and hair alga started to grow well after nitrates and phosphates became undetectable and after GAC and GFO were in place. This could be just a coincidence but the timing is interesting.
Very recently, I siphoned off some interstitial water from the sand bed and measured the chemical levels. To my surprise, it contained 1-2 ppm of phosphate, no ammonia or nitrate, and 0.1 ppm of iron, even though the system's water has undetectable levels of iron and phosphate! Did I finally discover why my cyanobacteria did not respond to standard remedies? Is the sand bed condition the reason algae finally started growing?
Since the sand bed is my denitrification system, I did not want to disturb it by vacuuming it so I am in the process of using airline to siphon one gallon of interstitial water everyday. The first question to answer is whether I can reduce the phosphate level in the sand bed without disturbing the denitrifying bacteria, and if I do, will this finally choke off the cyanobacteria growth? After removing twenty gallons, the iron level seems down, phosphate level is about the same, cyanobacteria growth significantly diminished and nitrates still undetectable. I plan to continue removing water and measuring nutrient levels a bit longer.
What is next. In the coming year I would like to finally defeat the cyanobacteria growth (it's just not very nice to look at) and be able to grow a wider range of macro algae in the display tank while keeping the fish healthy. I also want to understand what's happening in the substrate to produce the high phosphate level.
Dan
The set up. Forty gallon breeder tank, glass top, two T5 lamps, small powerhead for circulation, Sterilite sump, DIY GAC reactor, DIY skimmer, 165 gallon per hour circulation from tank to sump, two 120 watt equivalent 5000 K CFL bulbs over the sump, local macro in sump. There is a two inch silica sand bed and a collection of granite stones.
Stocking history. Started with local macro algae on rock. Could not keep it alive. Who can't grow algae?!? Snails, hermit crabs and Asian Shore crabs went in next followed by grass shrimp. Continued to attempt keeping macro algae. Then came the Killifish and Pipefish. Moved inverts to the sump because the fish were harassing them. Here is a link to a short aquarium video taken around day 120.
https://m.youtube.com/watch?v=n1TzPQzFS2Y
Here is the nitrate and phosphate chemistry and stocking history.
How's it going now. Fish are growing. Killifish are mating. Pipefish are eating larger food and learning to keep it away from the other fish. Macro alga is finally growing well. It stopped dying after fish were introduced and now growing vigorously. Undetectable nitrate and phosphate levels.
Surprises or things I learned along the way. Even stocking an aquarium with everything straight from the Sound, the tank went through all the phases new salt water tanks go through. I never figured out why macro algae, including hair algae, wouldn't grow until fish were added and nutrient levels became undectable.
Nitrates did not start to accumulate until snalis and crabs were in the tank. No amount of dead macro algae resulted in detectable nitrate. Phosphate started accumulating with onset of regular feeding. Nitrate level went to undetectable even though there was no live rock or algae. The sand bed from the beach was apparently enough to set up denitrification. This not surprising in light of the work reported by Toonen's on substrates and plenums. In this studies nitrates did not accumulate as fast as ammonia was consumed, indicating that even shallow sand beds are acceptable environments for denitrifying bacteria.
http://www.advancedaquarist.com/2005/6/aafeature
Cyanobacteria started in earnest after the fish went in, and in this set up, it has resisted all standard "remedies" to date. I did not try Chemiclean, or Dr. Tim's yet. The use of GAC seemed to have no impact on cyanobacteria growth and GFO while it brought phosphates down to an undetectable level, had no impact on cyanobacteria growth. Macro algae and hair alga started to grow well after nitrates and phosphates became undetectable and after GAC and GFO were in place. This could be just a coincidence but the timing is interesting.
Very recently, I siphoned off some interstitial water from the sand bed and measured the chemical levels. To my surprise, it contained 1-2 ppm of phosphate, no ammonia or nitrate, and 0.1 ppm of iron, even though the system's water has undetectable levels of iron and phosphate! Did I finally discover why my cyanobacteria did not respond to standard remedies? Is the sand bed condition the reason algae finally started growing?
Since the sand bed is my denitrification system, I did not want to disturb it by vacuuming it so I am in the process of using airline to siphon one gallon of interstitial water everyday. The first question to answer is whether I can reduce the phosphate level in the sand bed without disturbing the denitrifying bacteria, and if I do, will this finally choke off the cyanobacteria growth? After removing twenty gallons, the iron level seems down, phosphate level is about the same, cyanobacteria growth significantly diminished and nitrates still undetectable. I plan to continue removing water and measuring nutrient levels a bit longer.
What is next. In the coming year I would like to finally defeat the cyanobacteria growth (it's just not very nice to look at) and be able to grow a wider range of macro algae in the display tank while keeping the fish healthy. I also want to understand what's happening in the substrate to produce the high phosphate level.
Dan
You might want to get rid of those Asian Shore Crabs before they get large...very destructive critters.
