EI Or PMDD?

[plantbrain]

I seal the dry section of the wet/dry filters and reduce the spill over into the weir boxes to about 3-5cm.
I use duct tape, but some suggested gaffer's tape to seal up any air leaks in the wet/dry box section.

The goal is to prevent exchange of gas.
CO2 can still degas there, but it just gets redissolved since it cannot vent.

Good if you have a fish only tank, but bad if you want to add more CO2.

The wet/drys are still very good though.
I use them on all my tanks, but they need just a little modification is all.

Also, CO2 and O2 are independent, so adding more CO2, does not displace O2, likewise, high O2 does not displace CO2. Respiration of fish is a two way street still(CO2 and O2), so when we add CO2, we should also consider having really good O2 as well, this allows us to add more cO2 with less risk to fish health/reduce stress etc.

I use high current and high CO2 and lower light, this is the best scenario for fish and plant health.
Also makes management 10X easier.

BGA tends to be due to poor filter mainteance, flow etc, or low NO3.
Blackout (3 days search here for this) or EM antibiotics etc. with subsequent dosing and upping of KNO3.

I neglect the KNO3, I get it coming in slowly.

Algae and plants can be used in this manner to judge what needs done and "fix its".

Basic routine maintenance, some gardening is all that's left.
Much simpler, easier than all the other techy method,s test kits and what not.
Most folks have a goal of a nice planted tank with moderate growth, reduced labor and a little gardening.
So the method should reflect that with a logical step wise approach that uses methods most are familiar with and have few assumptions/skills required.

I also practice what I preach:

 

[dw1305]

Hi all,

Also, CO2 and O2 are independent, so adding more CO2, does not displace O2, likewise, high O2 does not displace CO2. Respiration of fish is a two way street still(CO2 and O2), so when we add CO2, we should also consider having really good O2 as well, this allows us to add more cO2 with less risk to fish health/reduce stress etc.

The reason for this is that high CO2 levels become a problem as the difference between the concentration in the water and the fishes gills approaches equilibrium, at equilibrium there is no differential, the CO2 doesn't diffuse into the water, and the fish asphyxiates. The combination of high CO2 and low O2 is the combination that is likely to prove fatal. However a fish may be stressed and suffering from hypoxia long before the obvious signs of distress occur, this is why I don't add CO2, even though plant growth will be improved by CO2 levels well up into the 100's of ppm.

The same applies to O2, it is the differential between the O2 conc. in the tank water and the fishes gills that affects the rate that O2 diffuses into the fishes blood, high O2 means quicker diffusion into the blood and gives the fish to withstand (but not necessarily enjoy) high CO2 levels.

The final factor is not all fish are equal and Anabantoid fish, for example, (Bettas, Gouramis etc.) from warm, still waters have adaptations (air gulping, the anabantoid organ etc) to allow them to survive low O2 levels, (warm water holds less O2 than cold water). Another factor is that the lower conc . of salts in the water the higher the O2 capacity (this is partially why you can stock less marines per volume of water than tropicals), and yet one more factor is atmospheric pressure, as this declines the O2 holding capacity of the water declines, meaning that if you want to keep fish from a warm water with a high oxygen demand (say Rio Xingu plecs) it is best not to live in Denver.

cheers Darrel

 

[plantbrain]

Hi all, A However a fish may be stressed and suffering from hypoxia long before the obvious signs of distress occur, this is why I don't add CO2, even though plant growth will be improved by CO2 levels well up into the 100's of ppm.

So what metric would you propose for a sublethal sign of stress that an aquarist could see and measure?

How about breeding events and fry? I've breed discus, which are more sensitive to CO2 than other species due to lower O2 at higher temps and their larger size, larger fish in general, are more sensitive to respiration issues involving CO2. Angels and cories and plecos and tetras etc.

Speculation answers little, our systems are not particularly natural and we have complete control of CO2/O2/light/ppm's etc. Obvious signs of stress are all most aquarist have to look for, but breeding is generally a good sign that the fish are doing well, even by standards that do not include nor have anything to do with plants/CO2 enrichment.

Dose makes the poison, not the mere presence of a gas/chemical.
Copper can kill shrimp, but at a correct dose, it's essential.
All or nothing mind sets do little good, particularly when you leave the issue unanswerable.
They are based on fear, speculation, not observable facts.

Maybe they are true.......but the statement above does not demonstrate that.
Breeding events and long life etc, good careful measurements with data logging with specific cases wherre breeding has occurred, brings skeptical questioning to such speculation.

Example:


All these angels are bred and raised in this tank, they have never seen any other aquarium. discus have breed at least a dozen times, cories etc, CO2 is at about 35ppm, light is low, about 25 micromols at the bottom, so CO2 demand is also low/easier to manage. We pushed the CO2 to about 45ppm for extended periods, more was the max the discus could tolerate without color changes.

We used a light thermo IR method to measure CO2 in situ using a data logger. No issues with KH/pH and accuracy to +/- 1ppm. Few aquarist have such equipment.

Such data/observations does answer the question reasonably.
You can make your own conclusion from there based on the results.

The same applies to O2, it is the differential between the O2 conc. in the tank water and the fishes gills that affects the rate that O2 diffuses into the fishes blood, high O2 means quicker diffusion into the blood and gives the fish to withstand (but not necessarily enjoy) high CO2 levels.

Perhaps, if they are getting it on and living and looking really healthy, eat like pigs, not shy, not sick, not signs of stress by any metric that's non destructive.........(Killing fish is not an option for most folks), I would suggest there's little basis for such statements. Show me some evidence in a practical aquarium. I've shown mine after all.

Where's this proof that it happens as you say? In planted tanks? ADA has a huge list of examples, so do most aquascaping contest, aquarium after aquarium, I look at fish differently, breeding etc.
I think those are pretty good signs things are going well, and long life.

The final factor is not all fish are equal and Anabantoid fish, for example, (Bettas, Gouramis etc.) from warm, still waters have adaptations (air gulping, the anabantoid organ etc) to allow them to survive low O2 levels, (warm water holds less O2 than cold water). Another factor is that the lower conc . of salts in the water the higher the O2 capacity (this is partially why you can stock less marines per volume of water than tropicals), and yet one more factor is atmospheric pressure, as this declines the O2 holding capacity of the water declines, meaning that if you want to keep fish from a warm water with a high oxygen demand (say Rio Xingu plecs) it is best not to live in Denver.

[/quote]

Very true, good points. George Booth speculated that his fish where more sensitive than my discus since he lived high altitudes. That was 12 years ago I think? I had measured 35ppm, he had measured 15ppm or so, I had 2.5X more light though. Measurement errors and assumptions could also easily explain the difference as well.

I sold 230 Blue diamonds from that batch of 5 adults.

I have plenty of Rio Xingu plecos. Among my favorite fish as a whole.
Still, I think the points about CO2 being a higher risk for fish than say what many suggest, nutrients like NO3 etc, is much better founded. When used judiciously, CO2 is not an issue to long term health, when used carelessly, it's the no # 1 killer in the plant tank hobby.

Still, that is a human management issue/problem, not the fact that we can use CO2 well and still have a long term healthy place for fish where they can breed, eat like piggies etc.

I have a non CO2 planted tank, works very well. But I am on both sides of the fence, CO2 also.
Both can be done well, there's strong evidence this is the case.

Regards,
Tom Barr

 

[chris1004]

Hi Tom (plantbrain),

When you refer to lower lighting levels what sort of WPG figures would you be using?

I know the WPG rule is only a rough guide and there are also other factors in play i.e. reflectors, water depth/clarity, height above water of lights type of lights, biomass. etc etc.

But in my instance for example my lights are 6" above the water surface with reflectors, 20" deep tank and gin clear water. At the moment I have 2WPG of T5 HO lighting and I'm seriously looking at decreasing it following your sound advice in this thread but what in lamans terms would you suggest I aim for. Are there any pointers or further practical advice that you can give me. I understand it largely depends on what plants I have aswell. Mostly I've come to really like the various crypts having tried many varieties but as I understand it Crypt Parva needs a lot of light which is what I am growing as a foreground plant.

Love your tanks by the way.

Regards, Chris.

 

[AverageWhiteBloke]

Sorry for not replying sooner I've been away working. 🙁

The wet/drys are still very good though. I use them on all my tanks, but they need just a little modification is all.

This has made my weekend 🙂 pure genius. My biggest fear was that this system was not fit for purpose as I bought it when I gave up planted tanks for fish only system. Water change this weekend and I have an idea involving some cling film and elastic bands. 8) Another problem sorted.

BGA tends to be due to poor filter mainteance, flow etc, or low NO3.

I clean my two tray filters on a 15/30 pattern as one on the 15th day the other on the 30th of each month, I also do a 30% change with dechlorinated and warmed water once every two week. The flow is quite good as the weight of the water dropping through the opening in the lid circulates well most of the plants even furthest away can be seen moving in the current. As for the NO3 I'm working on that now, question is would I be better increasing NO3 on its own while keeping my current dosing schedule or increasing the amount of both macros and micros in line?

I believe the O2 should be ok, temp is 24 deg medium stock of fish and as Tom said my filter is quite effective at gassing/de-gassing the column 02/co2 respectively. Also the fact that the lid also has water in it I suppose this offers more of the surface area to the air which would also would help.

 

[dw1305]

Hi all.
I wrote "However a fish may be stressed and suffering from hypoxia long before the obvious signs of distress occur, this is why I don't add CO2, even though plant growth will be improved by CO2 levels well up into the 100's of ppm." and Tom wrote "So what metric would you propose for a sublethal sign of stress that an aquarist could see and measure?"

I've never kept fish with added CO2, so unlike Tom (PlantBrain) I have no personal experience to offer, but there is quite a lot of literature (from the Aquaculture industry) that suggests prolonged exposure to sub-lethal CO2 levels will have long lasting effects on fish health.

The technical terms are "hypercapnia" & "nephrocalcinosis", and this is the Google Scholar search for "hypercapnia & aquaculture" <http://scholar.google.co.uk/scholar?hl=en&q=hypercapnia aquaculture&um=1&ie=UTF-8&sa=N&tab=ws>. A lot of these references concentrate on Sturgeon, Trout and Salmon (fish from clean, cool, highly oxygenated waters), rather than the much more pollution tolerant Channel Catfish, Carp or Tilapia.

The below section is abstracted from:
"Water quality and welfare assessment on United Kingdom trout farms"
CM MacIntyre (2008) Ph.D. Theses Aquaculture University of Stirling
<https://dspace.stir.ac.uk/dspace/handle/1893/434>

".....Carbon dioxide is toxic to fishes because increases in ambient CO2 concentrations result in the fish being unable to excrete endogenous carbon dioxide, leading to CO2 increases in the blood, known as hypercapnia. As a result of this, the blood pH decreases, leading to acidosis, reducing the oxygen carrying capacity of the blood in a process called the Bohr effect. The reduction in blood pH weakens the bond between haemoglobin and oxygen molecules, resulting in the release of oxygen molecules which then passively diffuse into cells that have a low partial pressure of oxygen. This effect has been observed in salmonids at water concentrations of CO2 of around 20 mg/L* (Westers 2001). Danley et al.(2001) recorded reduced growth in rainbow trout over a 90 day experiment with CO2 concentrations up to 45 mg/L, but there was no report of significant mortalities at this level. Clinical signs of carbon dioxide toxicity include moribund fish, gaping mouths, flared operculae, and bright red gill lamellae (Summerfelt 2002). A well known effect of CO2 in conjunction with hard water, is nephrocalcinosis (Harrison 1979a, b, Smart 1981, Fikri et al. 2000). This chronic degenerative condition of the kidney is characterised by calcareous deposits (Harrison & Richards 1979; Smart et al. 1979). The white gritty kidney deposits consist of calcium salts, occur within the ureters on the surface of the kidneys, and the kidneys become swollen, sometimes with fluid-filled cysts (Harrison 1979a). The kidney is a major haemopoeitic organ in fish, and blood haematocrit values and haemoglobin content decrease in affected fish (Yurkowski et al. 1985). Severely affected fish become dark in colour, have a swollen abdomen and most of the functional kidney tissue is destroyed (Harrison 1979a; Yurkowski et al. 1985). Nephrocalcinosis occurs when natural CO2 levels in the water are high and/or when additional oxygenation is used to increase carrying capacity, and the total amount of metabolic CO2 excreted is increased as a result (Harrison 1979b). CO2 levels of 12mg/L induce nephrocalcinosis, with higher concentrations increasing the prevalence and severity of the condition (Harrison 1979b, Smart et al. 1979). Although CO2 level is a primary factor in the induction of the condition........"

*mg/L. is equivalent to ppm (H2O has a density of 1g/ml, and there are a 1000g in a litre, and a 1000mg in a gram and therefore 1,000,000 mg/L.)