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Oxygen in a planted tank.

andyh

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binned it after a week, it drove off all the co2 and caused a STAGHORN out break due to co2 instability!

I just made sure my flow was good!
 

plantbrain

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clonitza said:
What is the optimum oxygen level range in a high-tech planted tank? What is the best practice to keep that level? Does waste in external filters influences COD (Chemical Oxygen Demand) or it's not relevant, if it is, how often should the canister be cleaned?

Cheers,

I'd say 6-10ppm depends on Temp and time of day, but in general.
Use a wet/dry filter correctly for tanks 90cm or larger.
Yes, but so does cleaning frequency and other dependent variables(soil vs plain sand etc, rates of plant growth, quality of the growth vs sloughing of dead plant leaves/stems etc).

I tested canisters vs wet/dry filters and frankly........they kick the living snot out of the canisters.
In terms of CO2 and in terms of O2, wet/drys cannot be beat.

They are not particularly practical for small tanks, but they have not made small ones for smaller tanks.
Not much $$ in it for them to make those.


A typical CO2/O2 range is high CO2 most of the 24 hour period, long slow rise/decline for CO2. O2 as well with about 6-9 ppm ranges. CO2 might only drop from 60ppm when on to 20ppm when off.
Surface scum is much higher.

In the wet dry systems, the O2 was 7-11ppm.
The drop from 60ppm of CO2 to 3 pm occurred in about 45 minutes.
Very rapid. The higher nighttime O2 is likely due to the high exchange rate and lack of surface scum.

Bottom wet/dry chamber is sealed FYI and the over flow is only 4-6cm drop.

Each treatment had 3 replicates and different tanks and had high flow and high plant biomass(100% coverage).
Only by measuring and data logging CO2 and O2 over time, can you make such observations.

But the CO2:O2 ratio is good to measure fish health, eg we CANNOT talk about what is a safe CO2 ppm without also knowing what the O2 is as well. Since respiration is CO2 and O2 exchange, the concentrations of both are critical to make any assessment. These 2 gases change within minutes and thus are very rapid parameters, they are also critical to livestock.

Nutrients are far less critical, even if most forums spend far more time worrying over such minor details. People kill and gas fish weekly on most forums, killing them via KNO3? After 15 years posting and reading many forums/mailing list on the web, I have still yet to have seen someone do this.

I used an oxyguard CO2 monitor and a Hach LDO data logging HQ40 to measure the CO2 and the O2.
They make nice O2 meters for somewhat reasonable $$$.

Simple spot test kits can be a little bit useful, but they are generally never measured over the entire day/ cycle or 24 hour period, that is what is telling, not a discrete single point in time. No self respecting or respect limnologist would use or present data like that to make a general conclusion about a planted lake, stream, pond or river about the CO2/O2.

It also greatly depends on WHERE we take the measurement also.
I chose the upper 10cm near high flow in each aquarium.
If I chose the lowest flow, then these values will change and be less even.
Or if I chose deep within the plant beds, the CO2 and O2 would also be very different, or right at the sediment water column interface.

ADA's lily pipes are bad as far as I am concerned(need not fear ADA fanboys, I have a lily pipe on my 60p), while you can lift them up a bit to get more movement, this is also noisy. My solution was to add a tiny power head near the surface to add the flow required and without make a lot of bubbly noise. They also break if you move them without being very careful(done this a couple of times now). As water levels drop in tanks due to evaporation and us not topping them off daily etc, this changes the O2/CO2 exchange rates as well, this does not occur in wet/dry sump,s only the level in the sump changes, the flow characteristics in the tank itself remain constant.

Thus degassing and enrichment remain fairly constant regardless.

So dialing in a stable good rate of CO2 is easier. In canister filter systems, the CO2 is far more able to gas your fish and smaller changes will have a larger negative impact. So we get more fish security and more wiggle room dosing using a wet/dry.

But make sure to seal the sump wet/dry tower section good, otherwise the CO2 will degas.

Regards,
Tom Barr
 

nry

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I wonder then - many suggest that increasing flow in the aquarium is done to improve nutrient circulation (i.e. CO2 and the ferts). This is why I added a Koralia Nano to my tank recently.

Does the likely increase in O2 from increased flow have a noticeable part to play in why increased (improved with luck!) circulation is a benefit? I would assume that the answer is yes.
 
A

Anonymous

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Thank you for taking time to write us Tom, I really appreciate it. A couple of my friends have sumps on high tech aquariums and have great results with them, unfortunately I don't have space for one and I've wanted to know, taking in consideration the fact I need to seal the wet/dry area and that I want to replace my jbl canister filter in the future, if I could achieve similar results using a wet/dry Eheim canister filter

Anyway because I have an O2 test kit I'll make some tests during the photoperiod and after and post the results.

Cheers,
Mike
 

dw1305

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Hi all,
I tested canisters vs wet/dry filters and frankly........they kick the living snot out of the canisters.
In terms of CO2 and in terms of O2, wet/drys cannot be beat.
I agree with Tom as well, wet and dry trickle filters are very good for gas exchange, which also increases their biological filtration potential.

With apologies for the cross-post, but there are some more details of why they are so effective here: <http://plecoplanet.com/?page_id=829>.

cheers Darrel
 
A

Anonymous

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So I've made an O2 test with 20x (net) / ~15x (real) turnover, canister cleaned, water surface movement minimal and the O2 levels were between 8ppm and 10ppm unfortunately using this turnover most of the CO2 gassed out (PH remained around 7.5 24h) so I've cut down the flow to ~7.5x real and the PH dropped down to 7 (checked after the lights went out) and 6.5 (checked in the morning) CO2 added 24/24.

I'll run another O2 test with this turnover and I'll come back with the results.
 

dw1305

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Hi all,
So I've made an O2 test with 20x (net) / ~15x (real) turnover, canister cleaned, water surface movement minimal and the O2 levels were between 8ppm and 10ppm unfortunately using this turnover most of the CO2 gassed out (PH remained around 7.5 24h) so I've cut down the flow to ~7.5x real and the PH dropped down to 7 (checked after the lights went out) and 6.5 (checked in the morning) CO2 added 24/24.
This is interesting, my suspicion would be that the O2 levels will be fairly similar in both cases.

Can you give some details about the tank, particularly what was the initial dkH of the tank water? the bioload would be interesting as well, I assume there are no livestock present? so in this case how heavily planted is the tank?

cheers Darrel
 
A

Anonymous

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I guess a picture is better, my 4x24w t5 100l tank:

2mebqwz.jpg


The dKH is around 6-7, dGH 8-9 (used to have over 15 last year before using RO mineralized water), the bioload from fish is rather low (around 20 little guys in there) most of it is from plants and the peat moss in the substrate that's getting me nuts when I pull the plants (an experiment of mine, the last one :lol:)

Well things are going ok, still have algae but plants are growing like there's no tomorrow. Found out that I need to dose around Nitrogen 20ppm at least using this light level (some plants sopped growing at 10ppm - lindernia variegated is one of them, now it's back on track).

Cheers,
Mike
 

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