Macroalgae Nitrate Export

[bioload]

How fast will MNE take to occur...........Well Let's find out....sort of.

Tank 7"x7"x17"
Airline with valve
Terta Tec Deep Pump
Water volume = 3 gallons
Algae = Caulerpa and Chaeto

Setup


Day 1 - Noticeable change in Nitrate

[Megalodon]

I'd like to also know what ratio of phosphate and nitrate the chaeto consumes.

Do you have a phosphate test kit as well?

[Greenmaster]

I'll watch this one... do you have turnover or is it just the closed tank?

[bioload]

Originally Posted by Megalodon

I'd like to also know what ratio of phosphate and nitrate the chaeto consumes.

Do you have a phosphate test kit as well?

Hi Megalodon, I managed to dig up my phosphate kit and will include as well.



Greenmaster, the algae scrubber is closed at the moment. I might wait till all nitrates are removed from the closed system before I introduce any flow from the display tank.

Let's say it takes 5 days to remove all nitrate from the 3 gallons. I'll set the flow to match that turnover. Don't think it would make any difference to the algae, but I would like to see if I can keep the effluent of the scrubber at O nitrates.......assuming it even works at all.

[Greenmaster]

That sounds good but maybe not the best thing... Think of it this way. if you put a plant in a acrylic box and measure the amount of CO2 in it then seal the box and wait till all the CO2 is gone the plant won't be happy... then you determined the rate at witch it took CO2 out of the air and got the air to be pumped into the box at that rate your plant would have huge die off and not be able to remove as much as otherwise... on the other side if you were to give it elevated levels of CO2 it would take off and start to convert more CO2 then before.
Now with your experiment the plant will not die because you are providing CO2 but the nitrate/phosphate is what it uses to grow so you will have more growth in the beginning and less as the saturation drops. I like the idea of the experiment and would love to see the results but I believe that once you have determined the amount being removed you would be better off to allow high flow to make sure that the plants are getting as much access to the nitrate/phosphate as possible. When the plants take off you will need to prune them to ensure that they have space to grow.
A lot of people make the mistake of letting the plants grow till they fill the refuge and thing that volume helps with "cleaning" the water.
The other one is your idea, they think that the plant de-nitrate is the same as an aerobic where it is ideal to have the water come out the end at no nitrates. With plants however you will have good growth at the water entrance and less as it gets "eaten" by the plants at the far end you will have minimal growth on the plants as they are not getting the rich fertilizer.
I'm not trying to talk anybody down I'm just trying to help people understand the biology of the system and why it works. I'm more then willing to answer more questions... or if you want me to shut up I can do that too... I want to see how this experiment turns out .

One question... what lighting are you using? (plants need; CO2 provided by the bubbles faster is better... I would also put the bubbles at the bottom of the tank, nutrients provided by the fish nitrate/phosphate, and light, in order to grow well... more growth means more nitrate reduction)

[bioload]

At the moment the only lighting for the algae is an adjacent window, but I doubt if the tank is getting any direct sunlight though. Once I can get my hands on some rigid tubing (one of those boxes in the basement) I'll lower the airline and add a diffuser.

I'm regulating the flow to the algae scrubber, I'll call it that for now since there is no sand or rock that you might find in a typical refuge, mainly out of curiosity. However, I see your point with regards to providing a higher concentration of nutrients to promote growth, and subsequent uptake.

[SeaHorse_Fanatic]

Add a light if you want to really have some proper nutrient export. Photosynthetic processes are what uses up NO3 and PO4, so you should add supplemental lighting.

[Greenmaster]

Originally Posted by seahorse_fanatic

add a light if you want to really have some proper nutrient export. Photosynthetic processes are what uses up no3 and po4, so you should add supplemental lighting.

+1

[bioload]

Day 2

[Greenmaster]

Coming along