BBA is related to stable CO2.

Stable CO2 allows the plant to adapt to the Carbon available.
I'm not just saying this, There are some very good biochemical and enzymatic reasoning behind it....and it makes a lot of sense.

Plants make an enzyme called Rubisco. This represents the largest fraction of nitrogen and protein in the plant and, well....the entire world!

It's an expensive enzyme to make.
Plants up and down regulate its production and also degrade it for use in other situations when in excess(say under low N levels but ample CO2). Plants are lazy(or "efficient" depending on your view). If they have too much Rubisco not doing anything useful, they will degrade Rubsico, allocate and partition the Nitrogen to other enzymes and/or tissues.

So aquatic plants certainly do adapt to high, medium and low CO2 content, there's plenty of recent direct evidence for this in aquatics and most every terrestrial plant as well.

It's not a special case adaptation to their environment in other words.
It's very broad, "generalizable" and a common sense type of plant regulation.
No plant should be without it. Rubisco is the largest fraction of protein in most any plant. Plants make sugars from this reduction of CO2 and that's their "food".

In a non CO2 enriched tank, plants adapt to low CO2 (this takes maybe 1-6 weeks depending on the species) by making a lot of Rubisco and this extra Rubisco scavanges for low levels of CO2. As long as the CO2 is nice and low, the plant maintains this concentration/enzymatic activity of Rubisco.

Contrast this with a high CO2 tank where the plants get a stable level of say 30ppm.

These plants become fat and lazy (efficient). They do not produce much CO2 fixing enzyme because, they do not have to after a few weeks of adaptation. We see plants slowly acclimating to such tanks just like the non CO2 ones.
Once they settle in, they really take off. They can devote far more resources to growth than CO2 uptake.

Now ask yourself this question: what would happen if I added CO2 to a non CO2 adapted tank? Would this hurt/harm growth? No, but the CO2 would be removed very fast and then the Nitrogen PO4, K, Traces etc.

This is fine if you add the other downstream nutrients like N, P, K, Fe etc to account for this increased demand. But if not? Folks think enriching w/CO2 = algae. They often see a peroid of rapid growth, think everything is fine, then slowly algae appears. Many non CO2 folks ike the idea they do not need to add ferts, the fish waste alone supplies the plant's needs. They add just the CO2, they generally run out of nutrients after a few weeks and plant demand cannot be supplied/balanced with the removal of CO2 limitation from the fish waste alone.

Now the next question you most likely should ask about this: what happens if you take a high CO2 adapted aquatic plants, and place it in a tank with 50% less or 75% less or 90% less CO2 and also add high light (this will remove the CO2 much faster than the lower light non CO2 approach!!) ??

The plants now have very little Rubisco since they are adapted to high CO2 and are "lazy". You also add lots of light which makes the uptake demand (but not supply) faster.

Your plants cannot respond quickly to this low concentration. It takes time for the plant to make more enzyme. It takes them a few days, weeks to make more. So if the CO2 drops say from 30 ppm to 15ppm during the day, the net effect is that the plants are CO2 "starved", limited for a peroid of time. This is not a black and white effect, there is a gradation of carbon limitation over a wide range. After a few weeks of stable conditions, the plants are fine again, but now the adult algae are there and tough to get rid of. So you pick and clean things up and prune and pick on the adult algae and keep things in good shape for the plants.


Suppose you are NO3 limited? Then the ability to make the enzymes required when conditions change like this becomes even more troublesome.

Alagae have very low CO2 demand, but they also have far less trouble responding to CO2 changes in their environment. They prefer high CO2 as well, but have much less trouble with variations and making Rubsico or HCO3 uptake and can respond very rapidly to such changes, whereas the plants, which are much larger, take more time.

That time difference in CO2 adaptation allows some species of algae to get a foot hold and germinate. Think about in terms of nature. It's a good adaptation if you are an alga to respond quickly to CO2 variation.

If you have low light, there's much less issue with all this and shows why it helps to reduce lighting rather than limiting NO3, PO4 etc.

Light first drives CO2 uptake!! Less light= less CO2 demand.

Now why do take grow wekk for awhile, then get algae a bit later? As plant biomass increases, so does CO2 uptake, assuming the CO2 is going to be the same the entire time is a bad idea. If you have 3x the plant biomass , you are going to have a lot more CO2 demand.

Therefore: good consistent pruning, adding a bit more CO2 as tanks grow in well and biomass increases, watching the CO2 conternt over the lighting cycle(rather than one discrete point during the day) and giving things time once you do stabilize the parameters will help a great deal.

Aquarist have a lot of issues with CO2, they whine, they cry, they bellyache, they speculate, they blame the innocent players such as NO3 or PO4 or the advice. But few really look at CO2 critically in terms of of why it helps, why it works, or also, why it does not work sometimes. My CO2 is high and I'm certain it's perfect, why do I still have algae with EI or with ADA?

Then the counter, why doesn't Amano or Tom Barr, or other folks have algae then?
We add a fair amount of nutrients, I use the same type of substrate as Amano and a lot of other substrate, and probably more light than Amano, most of you use more light than Amano BTW.

Well what is the solution then? Keeping a closer eye on CO2, making sure things are stable, kept up on, pruned well, being a lot more humble and doubtful of your abilities and assumptions about what is causing issues for you. If you have an issue, try and figure it out, not by the advice so much, rather test and give the test time.

Work from this downstream appraoch if something does come up: light(easy to change generally)=> CO2 (often hard to measure, takes many readings and a careful eye)=> NO3=> K=> PO4=> Mg=> Ca => traces.

EI takes care of the nutrients, light and CO2 are all that are really left.
Obviously, from and management prespective, less light(duration to some degree within a fairly wide range and more importantly, intensity) will help reduce the deamnd for all down stream nutrients since it drives CO2 uptake and carbon regulates N, which regulates other processes such as enzyme production of Rubisco.

Patience is another issue, how long should we really try and keep up on things?
No simple answer there, but if you can do a fair amount of work to do that for a few weeks, typically 3 or so, then you should see some improvement.
If not, change the approach.

It does not mean or imply the tank will be spotless, but it should be on that way, no new algae growing/formed etc.

Regards,
Tom Barr

Tom,

This was a very interesting post. I currently have a 30 gallon tank with pressurized co2. I'm in the process of setting up a 50 gallon tank. I was planning to move my co2 setup to the 50 and trying excel on the 30 which now has the pressurized co2. My 30 is running very well and is free of algae except for a few spots of gsa. I haven't had to scrape off algae on the glass for almost 3 weeks, so I'm a pretty happy camper right now.

My question is am I setting myself up for an algae problem if I switch the 30 to excel ? I'm not adding co2, but I am adding carbon so maybe this is a different situation. I could try excel on the new 50, but it obviously is more expensive. Should I just leave the 30 alone ?

Your comments on the stability of co2 levels caught my eye. For those using DYI co2 one of the problems is the inevitable variation of co2 levels. Is this another algae issue ? It almost seems that going excel or the Walstad route might be better with respect to managing algae.

One thing I think I've learned is that algae is not really related to too much of this or that. It's the relationship and interraction of nutrients that really seems to count. Phosphates are good for plants. Phosphates with little or no nitrates are good for algae.


Henry Hatch

Hey Tom - Great post! Like Henry your comments on CO2 stability caught my interest. In a fully automated system (solenoid attached to pH probe) how could you really see any fluxuation in CO2?

Wello it depends on the ability of the CO2 reactor and pH controller to respond to the readings and changes in the system.

Most seem to assume because they have a pH controller, everything is fine and dandy.

You need to have a good system in place to add the CO2 rapidly for the control function to operate properly. Some seem oblivious to that issue

But the post does explain why a stable system can prevent BBA and maintain good plant growth and less stunting that someone who merely adds more than 30ppm at least when they test.

If it takes 2-4 hours for the CO2 to get to the right level, after the lights are turned on, that's bad, but if the CO2 ppm is 30-40ppm from sun up, till sun down, then things will do quite well.

A day or 2 of poor CO2 will not matter if the CO2 ppms have been stable for weeks etc as long as they are broght back up later.

Excel should do fine, but tyou'll get better results from CO2, and Excel with less lighting.

Less light= more wiggle room with CO2 and Excel.

Regards,
Tom Barr

Since lightning is the easiest part we can controll, could one say we actually should decrease intensity of light during the day over the week to certify we have stable CO2?
roughly said using same CO2 bubble/second:
Monday: High light 6 hours + low biomass = 30ppm CO2
Wednesday: High light 4 hours + medium biomass = 30ppm CO2
Saturday: High light 2 hours + high biomass = 30ppm CO2

Well roughly, yes.

It'll take a certain amount of time to remove 30ppm of CO2 from the water in a closed system.

More light, more uptake.

Longer light, more uptake.

There are practical limits, such as time to get the uptake going and started upon initiation of the light treatment. In the shorter time frames, this becomes more critical.

Length of duration can be a factor also, I'd suggest 4 hours and 8 or 10 etc and look at it from those time frames.

Regards,
Tom Barr

Great article.

Now where to start.

I can summise my beginnings in plant keeping as sub barr....ermm par :P

I recently transferred my main tank from a 50 gallon to a 150 gallon (2x2x5) two months ago. I always dealt with every kind of algea you can list. Spent way to much money on bottled ferts. Which last week I solved by getting my dry ferts from Aquarium Plant Food - hobbyist taking care of hobbyist … | Planted Aquarium Fertilizer. I can say one thing about the ordering experience from that site. Exceptional.

Prior to reading the articles here on proper CO2 measuring ,I always dealt with the cycle of, at each weekly 50% water change I was always scrubbing and pruning algea. BTW pruning algea and not plant growth sucks. I have ordered some 4 dkh since I would rather trust a lab certified solution rather than my own math deficient dyi. Now the only algea I have been getting is very minimal amounts of gsa <- Green Spot Algea?. C02 is pressurized and distributed via two Reactor 500's.

Now to the bones of the pending question.

Water params via API testing solutions performed 2 hours before lights out.

PH - 7.2
NO2 - 0.0
NO3 - 0.0 - 0.5 two different test kits give the variance
P04 - 2.0
NH4 - 0.0
CA2 - 40 ppm
FE - 0.5
KH - 7.0 dkh

I dose via the EI for 125 gallons to account for the overflow, wood, and substrate mass.

KNO3 - 1.5 tsp T/TH/SA/Sun
KH2P04 - .5 tsp T/TH/SA/Sun
CMDD - .5 tsp M/W/F
FE - to maintain 0.5
Rock Salt - 1 tbsp per 10 gallons of water changed (keeps my cichlids happy)

Water changes are on Sunday.

I have naturally hard tap water 7dkh so I don't dose GH booster.

480 watts of HO T5 lighting from Catalina Aquarium 6 X 80W T5 RETRO.

Lights are on two seperate timers with 240 watts per timer. All six bulbs are 10,000k.

1 - 8am - 1pm
2 - 11am - 6 pm

Main filtrations is a Rena XP4 and a Beckett 325 gph into a dyi modified GE SmartWater filter with a 20 micron spun filter for water polishing.

I have a healthy fish load.

5 Demasoni . Well actually since all the females are keeping the one male busy right now its actually 39. 34 of them in floating breeder cubes and two more holding again.

3 Altolamprologus calvus (Chaitika) sub adults

4 Julidochromis marlieri (Burundi) adults

3 Clown Loach sub adults (no more snails)

14 Tropheus Duboisi sub adults

8 Lamprologus Multifasciatus adults

2 Melanochromis Auratus (temporary visitors)

Now the questions.

With a heavy planted tank would it be normal to see the NO3 levels that low at the end of the day? Prior to upping the CO2 (easily double as before) the NO3 would test from 10-15 ppm. Should I be dosing more KNO3 to compensate or will things over time settle down. If I"m understanding things correctly that with the increased C02 I have increased the uptake ("surge uptake") and eventually the plants will settle back.

Also how long after dosing could I test the NO3 levels and get the best reading of how much NO3 is being added after dosing.

On another note. I do notice when all the lights are on for the two hour period. Its almost as if a switch turns on in the plants when both lights come on at the same time. Almost instantly I get ??degassing?? from damaged parts of the plants. Ie. where I trimmed recently or a hole in a leaf. Could someone explain what that process is and why the higher light triggers that response from the plants?

You have some areas that can greatly improve things for you and the fish.
Rock salt: do not use this, use the GH booster.
Look up the salts, specific ions that are present in the lake.
Sodium is pretty low and Ca, Mg, SO4, K+ are high.
The Na is pretty toxic to plants(but not most algae generally), the others ions are plant nutrients :idea:

That should help.

More filtration would help and more mixing inside the tank, this will help mix the CO2 better.

GSA is a sign that the CO2 can be improved if you are dosing healthy PO4.
A slight haze might be present, but no more than that.
Less lighting can improve things also.
You ought to be able to get away with 280 w total, no midday spike or no switching on one bank and then the other in the rear.

For now, try adding only 280 w at any one time without any overlap spike.
Given your KH, I'd suggest switching to Tropica aquatic plant care, the chelator is better optimized for your KH than PMDD.
You should see a good improvement.

Mg, You ought to use the GH booster in place of rock slat and that would address the Mg as well, if not, add 1 teaspoon 2-3x a week. Tropica also has some Mg/K added as well.

I'd add about 30-35 mls of the Tropica weekly.
PMDD is cheap, but it's not that good and you have to add more and more frequently to get good effects, especially in harder water(Higher KH).

You will want to really focus on good CO2 from there.
Good mixing, good current, good surface movement without breaking the surface ought to help and prevent fish stress.

With lower lighting, Drop checkers etc this should not be hard to achieve.
This will maximize your light and allow much easier control of the plants and no algae.

Which is your goal anyways.

NO3 And API test kits or other test kits.
Of all the test kits I've heard and seen, the Lamotte and Hach are the most reliable for NO3 and PO4.

NO3 test kits can and do vary.
It cannot be helped.

They have accuracy issues.
So we use standard reference solutions to check their accuracy and calibrate them.

This is an added step.
One most aquarists do not do.
If they do, they tend to do it only 1-2x maybe and then assume from then on the test kit is right.

Reagents expire, we do things slightly different each time, batches of test kits vary etc. Plenty of sources of error.

Unless I've measured the test kit method against a known stock solution, I am skeptical.

You should be also.

With EI dosing and that amount of KNO3, there's just no way the NO3 are that low.

You have a decent fish load, you could even add a few more lamps of your choice or maybe a some O. ventralis which make a dramatic display fish at this size.
Not sure if you like those of Crypri's etc.

Syno petricola would also be very suitable and are good for eating snails etc(and shrimp but the other fish will as well).

It's unlikely you have low NO3 though..........very unlikely, you could have 2x the lighting and still have plenty of NO3 to spare.

So I'm thinking test kit issues.

See the how to make PO4 and NO3 reference solutions by Left C(or search Left C's post here).

I think if you do, you'll be mythed at the accuracy of the test kits and start questioning things much more as you should anyway.
We are often lulled into accepting that the test kits are accurate, when reality sets in.......we are more skeptical about test kit readings and figuring out what their meanings really are in relations to our tanks, fish health and plant growth.

But we should be and this is better, not worse.

Test the NO3 about 30 minutes after.
Dose only 1/2 the amount.
Then pre mix some in solution, then mix it well while adding it to the tank.
MEASURE IN 15 MINUTES.

That should do it.

With both lights on, you often and should see a lot more pearling of the plants, due to growth. This means more growth.

Some like more growth, others want slower growth.
This is more your choice.

The added spike of light in the midday adds some nice pearling without adding too much light for the whole day.

Many folks do not have the option to add extra light though or vary it.

T5 lighting is easy to manipulate however and offers lower lighting options with good even spread, as well as being very efficient watt use of light.

These and MH's are the way to go if you can afford them.
T8's and DIY are really a good choice for the folks with less funding or those that do not want to spend as much.

You might consider a pair of DIY in line CO2 reactors, for about 10-12$ each and replace those for the Reactor 500's.


Regards,
Tom Barr

I'll cut back the lighting to just 280 watts. The lights are staggerred inline (one on one off per switch) so I should be able to use half the lighting per half the lighting period to use all the bulbs. The lighting is centered over the tank so switching them back and forthe shouldn't be an issue I wouldn't think.

I do notice a slight haze when I look across the length of the tank.

I do run also in the tank a Rio 180 with a PowerClear attachement for extra posishing, and a Hydor Koralia 1. There seems to be a nice steady flow in the tank. All the plants exibit a small steady wavy motion. I do run a bubble wand across the back of the tank also to give more surface movement, to promote circulation in the hidden back corners, and giving fish CPR scares me :P. I have been considering adding an additional XP3 since I do have room in my DYI stand.

I'll order some GH booster right away and look for where to order Tropica to replace the dosing of the CMDD traces. I think I've been misunderstanding the purpose of GH booster all this time.

I had a feeling the test kit was giving faulty readings. What test kits would you recommend. I don't mind spending the extra money to be able to test properly.

I'll take a look at the DIY Reactors.


Not sure if I'm stating the trace correctly. I'm using the Plantex CSM+B.

To beat that is it permissible to have the CO2 switch on 3 hours before lights on?