Dosing CO2??

[3D-Reef]

The dust coating comes from adding a little more sand,to account for the loss of sand when harvesting macros.It really sticks to the grass but not to anything else.I don't add sand very often,just once in a while.

When I add kalk to the RO reservoir,any more than 1/2 tsp/8gals,I get the same build up on the grass.The Ph comes up to 8.3 and the Ca++ goes up to 400ppm.The evaperation rate is ~1.75 gals/day

All of the test kits are Salifert except for Ph,and it's made by Aquarium Pharmaceuticals.

The last large water change...40gals 2-3 weeks ago.

Additives...~1cup/week, Ca chloride-mixed at 2cups/gal of RO
Kent's turbo Strontium...5ml /week-mixed per instructions
Kent's super chelated Iron...10ml/week
Lugol's...2 drops/week
Kent's DKh buffer...3 tbsp/week
Kent's Tech-M Magnesium...as needed

No direct sunlight.

[Boomer]

3-D

On Monday, going to IMAC and need to get off this PC, it has been hrs on forums

[kae]

Originally posted by Boomer
Yes, they are decreasing the Alk just like corals do, both are using HCO3-, which is part of the Alk. True Carbonate Alk, CA is [HCO3-] +[ CO3--]. All of the coralline, Halimedia, etc, use up Alk and Ca++ just as corals. They produce and grow as a function of CaCO3 production either as Aragonite or Calcite. However, some alage do this more at night.

I think my question was not clear. What I would like to know is does Alk decrease when plants/algae (not calcareous algae) use HCO3- for their CO2 source to photosynthesize like in this equation?

HCO3- + H+ ----> CO2 + H2O

Thanks Boomer.

[Boomer]

Yes

[kae]

Originally posted by Boomer
Yes

Boomer, your answer made me confused. From what I've read and fromthis thread, I always believe that Alk does not change during photosynthesis if there is no calcification

Thanks for your help.

[3D-Reef]

Originally posted by Boomer
3-D

On Monday, going to IMAC and need to get off this PC, it has been hrs on forums

IMAC,sounds like alot of fun Have a good time!!

[graveyardworm]

The alk will decrease because the plant is removing the C from HCO3. So you no longer have HCO3, you are left with H and O3. Which are also likely to be used or converted further during the process.

[Boomer]

No David

The plant is removing the H /say and leaving more CO3 behind which increase the pH and lowers the Alk in the end. There is more to these reactions than this. Also, plants do not create ozone O3. This will help explain its complexity.

Photosynthesis and the Reef Aquarium Part I: Carbon Sources
http://reefkeeping.com/issues/2006-10/rhf/index.php

[graveyardworm]

Apparently I know very little when we start talking H+C-O3= but it was worth a shot.

I thought HCO3 was providing a source of carbon for marine plants. Isnt C Carbon? So wouldnt the plant be removing the C to satisfy its carbon needs?

[Boomer]

Yes, but you have to look at all the reactions taking place. Some plants can get their CO2 from HCO3- by converting it to CO2, which leaves " H and O " They then take the C out of the CO2 as their Carbon "C" soruce and give off O2 This loss of CO2 causes a net shift in the CO2 to be low, which raises the pH. CO3 can also be converted to CO2. Try reading the article it is all explained.

[graveyardworm]

I've browsed the article but havent fully read it yet.

[kae]

Boomer, would you please explain this statement.

Plants that do not calcify do not consume alkalinity. When they take up bicarbonate to attain CO2, they spit out OH-, leaving the alkalinity of the water unchanged:

HCO3- ---> OH- + CO2

That is what Randy has mentioned in this thread.

Thank you Boomer.

[Boomer]

Sorry Kae for not really answering you question earlier in a better way

There is nothing to explain. That is true. However, something I and Randy left out. Some plants are not calcifying or calcareous plants as we usually speak of them but do contain small calcium carbonate structures in their cell walls in small amounts, thus they consume some Alk. Some produce calcium sulfate. You may not think of soft corals at Alk users but many are as they have calcium carbonate spicules in their structure. Even things like sea urchins take up some Alk for their structures.

Since the plants are consuming HCO3-, a form of CO2 by conversion, there is a shift only in the pH, with no change in Alk. In this means it is the same as FW plants, which due not consume Alk but lower the CO2, which raises the pH.

HCO3- ---> OH- + CO2


This and similar equations are what pH is inherent to due to the shift I mentioned here;

As CO2 leaves the system it causes a shift in the ratio of CO2:HCO3-:CO3. At any pH there is an exact ratio of these. Anyone that has the same pH has the same exact ratio but the concentration may be higher. Since the ratio is the same there is no change in Alk. However, if the amount or concentration of the components of these ratios increases then there is a shift in Alk. This would take place in corals and plants that use HCO3- to produce calcium carbonate just like corals or if you dumped a buffer in your tank.


In NSW at 35 ppt that ratio is about @ 8.3 pH
<.4 % CO2, 93.6 % HCO3 - and 6 % CO3-.


Remmeber this is a ratio and not a concentration. So, if we lost HCO3- to plants, the Alk remains the same but the ratio above will shift to give a sligfhtly higher pH, so that new ratio may look like this .3 % CO2: 92.7 % HCO3- and 7 % CO3--

As I showed in a similar example on a post above, where two water samples have the same pH and differnt Alk we can do the same here where there is no shift in the Alk but there is in pH, a shift in Alk and not pH and a shift in both Alk and pH.


No shift in pH but consuming Alk

pH 8.3, Alk 2.25 meq / l = .4 ppm CO2
pH 8.3, Alk 2.0 meq/ l = .33 ppm CO2



No shift in Alk but different pH. Your -->where plants do not make calcium carbonate at all. The CO2 is lower and we have that increase in the ratio I posted above but still the same Alk.

pH 8.3, Alk 2.25 meq / l = .4 ppm CO2
pH 8.4, Alk 2.25 meq/ l = .28 ppm CO2



Shift in both Alk and pH

pH 8.3, Alk 2.25 meq / l = .4 ppm CO2
pH 8.4, Alk 2.0 meq/ l = .25 ppm CO2

[kae]

Thank you very much Boomer.

[Boomer]

You bet Kae

[Plantbrain]

Sarah et al,

I've been away doing research and playing with other things.
anyway, I've played with the growth of several macro algae and have some culturing methods to address.

I used CO2.
It did not do much relative to a control.
Actually nothing.

I did not predict this.
I predicted more growth.

This tank is packed also, so limitation may occur.

I also had a bought with cyano in another culture tank.
I tried quite a few things, made lots of mistakes on this tank in particular.

I tried every remedy for Red cyano and not one of them worked.
This was like the FW algae.

So I took FW approaches.

I reasoned that the focus should be on the plant/macro, not the noxious algae pest.

Adding CO2 did not help, nor any combo of ratios, etc, and I tried all sorts of antibiotics also etc, blackout worked well for 3 days but the cyano came right back, 3x a week 50-80% water changes never worked etc.

So what did work and amplified the growth a great deal?

Aeration, lots and lots of it.

You might not be aware of my old CO2 mist theory from the FW plant folks.

I can test it indirectly using O2 meters and CO2 [aq] measure.

But there is more to it in our case and the result is simpler in terms of a method for the macro algae hobby and I suspect seagrass strongly as well.

Cyano went away rapidly, never came back.
Plants have grown and looked very healthy.
I have very high biomass now.

I tried to filter all the detritus all also, that did not work either, but helped some against the Cyano and growth.

Steady NO3/Fe dosing helped, I also started PO4 dosing as the levels started to fall,m but that was only after heavily aerating.

So what is going on here?
The bubbles are sticky and they break up boundary layer around leaves/fronds. They also contain gas like CO2 and O2.
These are much faster in terms of Fick's 1st law of diffusion, for transfer.

This also mimics the ocean environment with the froath of bubbles near seagrass and a lot of macro habitats.

If you go inland on the bay side of Florida, you'll note how much more cyanos and diatoms you find, temp+low gas exchange is likely the cause.

Where there is higher current/aeration + plants, less cyano.
I saw this everywhere in FL, in CA, seagrasses are only found in higher light high aerated regions, which is all of CA coast

So this froath of aeration seems to produce the awesome growth.

I turned it off 4 times and waited, the growth reduces, and the O2 diurnal peak also declines(110% saturation to 95%), suggesting less growth. I also saw the return of pest algae.
Turning the aeration back on full blast: inside 1 week, the results returned to the original state and maintained strong resiliency.

I've done very well with macro algae growth in the past from tropical regions. I also had a skilter cranking in lot so aeration. The one problem tank also had a skilter, but the air intake kept getting salt spray and clogging. After addressing that and testing my hypothesis out a few times, it seems I can safely make some conclusions:

Stable high aeration is a key/significant part of heavy macro/seagrass growth.
This facilitates gas exchange and perhaps removes epiphytic pest/algae
Stable NO3 and Fe dosing are critical.
Ca and alk are also critical.
pH tends to be more stable
Bacteria tend to do better cycling.
Less detritus

I also recently developed and marine specific Fe supplement for marine plants/macro algae.

I do not sell fertilizers, but another vendor will be selling it dry and you can make up your own solutions.
It's about 20-100X less than commericial brands BTW and is specific to marine systems alk and pH, unlike most other products.
I have just started using this and am extremely pleased.

I am thinking of going back and attacking CO2 better using a gas tank etc.


Regards,
Tom Barr

[Boomer]

Thanks for the input Tom. Long time not see yeah

[Plantbrain]

Yea, I'm killing Calupera taxifolia with the state of CA and they have had lots of culture issues. Hard to show divers and do studies when it's got issues.

They had a guy before me that seems to have spent quite a bit of $ without any success. Some fiddling and tenacity and I got it back from nasty filth.

It's a weird plant, it'll grow great in the environment, but not as well in culture, which is odd, because.......it came from culture!!!

The chiller did nothing, many things did nothing.
I went back and forth a few times, as the Macros and noxious algae and epiphytes grow pretty fast, you can tell rather quickly if something works or not.

That's one advantage about growing macros and learning more.
Plants are slower to respond.

Regards,
Tom Barr

[reiverix]

In my heavily planted SW tank, I've twice turned off the skimmer (a leftover from when it was a reef) only to turn it back on. It pulls out virtually no skimmate but my tank won't function without it. I've long suspected it is only working as an elaborate aerator.

I've thought about running a line from the CO2 canister that injects my FW tank, but I've never saw anything that I could pinpoint to a carbon defeciency. So for that reason alone I haven't bothered. To be fair I don't have any vasculars at the moment.

[Boomer]

Often not reiverix as many marine pants use HCO3-. It is mostly unwanted plants that use CO2. However, a large use of HCO3- can still cause the pH to rise and they are converting HCO3- into CO2 = rising pH. If there in no pH issue then it is nothing to worry about.

[SherryCobySam]

Tom, Reiverix.

after a handful of macros came dead/dying I started reading.. I am trying to mimic the skilter effect right now by putting a sweetwater stone attached to 1/3 of the output of an airpump... near the hob filter intake of my 8 gallon (hopefully to be a macro /seahorse nano.

there are tons of bubbles. Far more than I ever had in fw co2.. and when i eventually get horses, I can dial this down some.. my question for now is will this alka selzter effect help my macros from what you know?

I am dosing no3 and put in a ricegrains worth of po4. tossed in some tropica too.

I am plant only for the moment so I can try just about anything.

when the horses come, would microbubbles be dangerous.. you hear a lot about 'gas bubble' disease, but lately that all seems to be an issue of infection, not actual bubbles.

have you tried misting with seahorses?

[reiverix]

I've never tried misting with my seahorses and I'm not sure it's something I'd want to try either. I try to keep good gas exchange in the tank though.

[SherryCobySam]

Riev, for the moment the tank has only snails and plants.. so I'll use the mist to get it started.

when you do mist, how bubbly do you let it go? the sweetwater stone under the intake will let me do everything from a light snow to alka seltzer.

[reiverix]

I can only talk from FW experience here. I use an ADA diffuser, which does produce very fine bubbles. The bubbles are blown around the tank via the outlet from a canister filter. Of course this is CO2 which can be dissolved quite easily in FW.

As far as mixing CO2 and saltwater goes, I know very little. I'll probably start experimenting one day and see how things go, but not in my seahorse tank though

I'm wondering if anyone here has tried Flourish Excel? It's a well known and popular substitute for CO2 in FW tanks. One side effect though, is that it is very harsh on some types of algae. Good for some tanks. Maybe not so good for the saltie side.

[SherryCobySam]

Sarah points out that Excel kills fw algae, and after using it to erradicate hair agae I can attest to the accuracy of this !

so I am worried about excel in a salt tank. but what I thought tom was talking about blowing into a Salt tank was Air -- and not pure co2 -- adding both some co2 and some o2 to a salt water tank..

maybe I'm getting confused?