Help. Plants Not photosynthesising

[GaspingGurami]

Tanks have just emerged from 4 days' blackout. During this period, only the filter and airstone is running. 50% water change every day, feed fish 1 cube of frozen bloodworms daily.

At the end of 4 days, tested water and results were
NO3: 5ppm PO4: 10ppm
kH: 3 deg, gH: 4 deg (after adjustment)

Some time before lights on, I turned on CO2, such that just before lights on, pH was 6, making CO2 to be 90ppm! even with the airstone running. Surprizingly, the fishes didn't show signs of CO2 poisoning.

I also added KNO3 to bring NO3 level up to 10ppm
Added 20 drops of LGA
Added 1.5 ml of Flourish Potassium to bring total est K level to: 10ppm

In summary, by lights on, I have an estimated:
Lights: 36 watt PL,
CO2: 90ppm,
NO3: 10ppm,
PO4: 10ppm,
K: 10ppm,
Fe: 0.056ppm (according to DMDD excel calculator)

Day 1:
Waited for bubbling to start. Nothing By dawn, all the fish are on the surface gasping

Day 2:
pH: 6.3, kH: 3deg, CO2: 45ppm.
Added 5ppm of NO3
Added 20 drops of LGA
Added 1.5 ml of K from flourish potassium
Didn't do water test to establish nutrient uptake for the previous day's running, so just aga aga top up.

Waited for bubbles to form, but still none.

Where did I go wrong now? What ingredient am I short of? My tank is 20litres + 10 litres from the cannister filter.

Thanks.

[juggler]

Is the airstone still bubbling?
Do you have many fish for your 20L tank?
What plants do you expect to be producing O2, or what plants are in there?

Observe more to see if plants are growing over next few days. Try to lower your CO2 so that fish is not stressed out.

[GaspingGurami]

Hi Juggler,

[quote:c7f488988c="juggler"]Is the airstone still bubbling?
Do you have many fish for your 20L tank?
What plants do you expect to be producing O2, or what plants are in there?[/quote:c7f488988c]

Airstone: Off when lights come on and vice versa (I'm keeping it this way till there's sufficient O2 to keep the fauna happy when the lights go off)
Fish: Around 20-30 pcs of neon tetras
Plants that usually bubble: A. nana, E. oriental, E. tennelus, Cabomba, Riccia.
Other plants that usually don't bubble: Banana plant, Egeria, C. thalictroides, L. repens, Java moss, Cladophora aegagropila.

[quote:c7f488988c="juggler"]Observe more to see if plants are growing over next few days. Try to lower your CO2 so that fish is not stressed out.[/quote:c7f488988c]
The last time I restarted my blackout tank few months ago, the plants bubbled within the same night. Now after 2 nights, still no action. Is this normal?

[geoffrey]

Lawrence,

It is really hard to pinpoint what exactly is preventing your plants from bubbling. You know plants need more than just light and CO2 to produce food, O2 a byproduct hence your bubbling.

What I can suggest though is maintain your light. That is your least of problem. Get your CO2 corrected. Yours should be on the high, given your fishes are grasping for help. Lowering it not below 30ppm will delight your fishes and also your plants. Work out a fertilising regime and don't believe everything the test kits tell you. Many a times we think we are providing enough for the plants when we actually may not.

For NO3, stay around 20~30ppm weekly divided into 2~3 doses, K at 10~20ppm weekly ought to be enough and PO4 at 2ppm should more than suffice. Dose TE using Fe as your proxy. TE coming from 0.5~1ppm of Fe weekly should be safe. Keep doing that, your ailling plants need time to recover, hence you won't see immediate results.

BTW, that 2ppm/week of PO4 can hold until you have diluted your accidental dose of extra KH2PO4. And you may want to consider using just KNO3 for your K and NO3 needs. This will make things alot less complicated, since lights and CO2 out, just KNO3, KH2PO4 and TE from your LGM to fiddle with.

In the meantime while you are beefing up your plants, make sure those algae that are already in the tank do not feast on the nutrients not intended for them. Use whatever you have in your arsenal to deal with them. Hack, prune or pick to manually remove as much as you can; blackout to deny them energy; peroxide to oxidise them; Yamatoes, cherry or blueberry shrimp; Otto, SAE etc. However, I do not encourage algicide or anti-bio. BTW, i think algicide is spelt wrongly

[hwchoy]

photosynthesis takes place when the necessary ingredients, primarily light and CO2 (plus other "minor stuff") is present. The basic end product is sugar/carbo (food for plant) and O2.

now, just because you do not see your plant bubbling does not mean it is not photosynthesising. most O2 produced will dissolve into the water, except when so much O2 is produced that it could not dissolve in time, or the water is already saturated with O2.

why is it necessary to have an airstone to aerate the water? do you really have so much bioload? In a planted tank with reasonable amount of CO2 injection I have never experience the need to aerate, which in fact may reduce CO2 concentration due to turbulence. I have fairly heavy bioload with only hairgrass and a lotus in the tank.

[geoffrey]

why is it necessary to have an airstone to aerate the water? do you really have so much bioload? In a planted tank with reasonable amount of CO2 injection I have never experience the need to aerate, which in fact may reduce CO2 concentration due to turbulence. I have fairly heavy bioload with only hairgrass and a lotus in the tank.

I like to take this out for discussion and at the same time solicit some feedback. I too do not aerate my tank with air and I let my CO2 runs 24/7. I am seriously considering aeration in my tanks after photo-period. Reason being a good level of O2 from the air helps the nitrifying bacteria to work better converting NH3 to NO3. Particularly helpful in a high bio-loaded tank as mentioned by Choy and also, less prone to algae since NH3 is quickly converted to NO3. Like to know if anyone noticed a difference between doing it and not doing it. What's your take?

[hwchoy]

are you using DIY or do not have solenoid? for me I do not aerate since I figure the water is already super saturated when the plants started bubbling so there should be more than enough to last the night.

[geoffrey]

Pressurised cylinders without solenoid.

I figure the same too, enough O2 to last the night. But lately I'm abit sceptical. I push my CO2 to a pretty high level and that goes through a reactor driven by a rapid flowrate. Which is sort of like driving out the O2 as in aeration or agitation to drive out CO2.

I also think that a tank rich in O2 tends to breakdown decay detritus and waste alot faster and efficiently, hence a clearer and cleaner tank.

[GaspingGurami]

Thanks for your replies Geoffrey and HWChoy.

[quote:993a3a7bc5="hwchoy"]photosynthesis takes place when the necessary ingredients, primarily light and CO2 (plus other "minor stuff") is present. The basic end product is sugar/carbo (food for plant) and O2..[/quote:993a3a7bc5]
Understood that part. And since the ingredients needed for photosynthesis are all present (assuming the tests are correct) the plants should be photosynthesysing well.

I know that they are photosynthesysing, as my latest test results show a reduction of NO3 and PO4 values, most probably due to the plants' doing. The surface scum is also indicative of the plants working to make sugars.

However, what I don't understand, is why the CO2 level is so exceptionally high. Since my last disaster, my bioload had almost halved. To add to that, my plant load has actually increased. So the high level of CO2 such that fishes are gasping is something that is confounding me since I has never encountered the same situation previously even with higher fish population and less dense plantings.


[quote:993a3a7bc5="hwchoy"]why is it necessary to have an airstone to aerate the water? do you really have so much bioload? In a planted tank with reasonable amount of CO2 injection I have never experience the need to aerate, which in fact may reduce CO2 concentration due to turbulence. I have fairly heavy bioload with only hairgrass and a lotus in the tank.[/quote:993a3a7bc5]

Neither have I seen such a phenomenon, and it has me scratching my head. Initially, I doubted the results of my tests and instrument. (I am getting 22ppm of CO2 with an airstone running fullpower!) However, when I see the fishes gasping, I can believe the numbers.

I want to state here that a bubbling soda drink tank is not my objective. I just want to have healthy growing plants, happy fish and minimum algae. However, I can't get the fishes happy without an airstone or the plants to supersaturate the water with O2 so I can do without the airstone.

I have checked and rechecked Lights, CO2, NPK, TE, temp, and they are the same as old parameters, and I recorded that under those parameters, I had healthy growing plants with good oxygen saturation levels.

Which leads me to think of the Eheim 2228 filter. That's the only thing that was different from the previous tank setup. I know it is overkill for a small tank like mine (I'm using it for the water volume than for it's filtration capabilities) But can a bacteria colony in that filter make so much CO2? That, I'm going to find out, by disconnecting the CO2 tomorrow, and see if the tank and filter can self generate that much CO2 on its own. And failing which, I'll probably have to give up my nickname!

Another day, another new complication to ponder. No wonder planted tanks can get so addictive.

[hwchoy]

[quote:a4c4c156f7="geoffrey"]Pressurised cylinders without solenoid.

I figure the same too, enough O2 to last the night. But lately I'm abit sceptical. I push my CO2 to a pretty high level and that goes through a reactor driven by a rapid flowrate. Which is sort of like driving out the O2 as in aeration or agitation to drive out CO2.

I also think that a tank rich in O2 tends to breakdown decay detritus and waste alot faster and efficiently, hence a clearer and cleaner tank.[/quote:a4c4c156f7]

I use solenoid mah

[victri]

There might be other factors that will affect the ph and skew your CO2 calculation. Watch out for stuff like rocks/stone, driftwood, gravel, etc.

Take a sample of tankwater and leave it overnight, then test for the ph.

[GaspingGurami]

[quote:eb110168be="victri"]There might be other factors that will affect the ph and skew your CO2 calculation. Watch out for stuff like rocks/stone, driftwood, gravel, etc.

Take a sample of tankwater and leave it overnight, then test for the ph.[/quote:eb110168be]

Hi Victri,

I thought like that too. Perhap some thing is buffering the pH. However, 1 look at the fishes is enough to convince me that the CO2 to O2 differential is too close. Therefore fish gasping at the surface, or breathing rapidly. This means, either O2 is too low, or CO2 is too high. No reason to doubt the tests or decoration since all the decor were in the tank from day one without such a strange problem.

In my previous post, I mentioned trying out an experiment, and here are my observations:

After a night of running the airstone, I woke at down to see that the fishes were at rest -- no gasping at the surface. So far so good.

Turned off the airstone to see if tank can produce its own CO2 that will be of a sufficiently high level for the plants to use.

CO2 level at dawn: 25ppm in spite of an air stone running the whole night.

All thru the day, I was told that the fishes were either dashing up for a gulp of air, or are at the surface gasping. I came back to observe the fishes at the surface gasping and plants not bubbling.

First reaction was to drop in an airstone, wrong move. Should have tested pH first. 1 hour later, fishes are more relaxed, not gasping, and not breathing rapidly. Tested pH and found CO2 to be 10ppm.

I am therefore confounded. Where did this high CO2 level came from, that is affecting the fish? Is the plant unable to use this form of CO2? (No bubbling)

Anybody want to hazard a guess?

[hwchoy]

you got coral chips in your tank? what substrate are you using?

[acidjc]

I noticed all my plants start to bubbles..when the right CO2 and lighs is injected.. lights is very important..

howvever I also add K and Iron into the water for evry water chg.

another thing, I also notice more bubble after water chg.. maybe the water is cleaner that why more light can pentarate in..

[Plantbrain]

You have 20-30 neons in a 20liter tank?
That's not good.

I've never found a need to run an airstone and I do not think the bacteria are in any need of O2 in a well run plant tank.

Amano might do it but he also would like to sell more beetles.
I do know he also turns the CO2 off at night, it's only added for the plants and the plants don't use it at night.

I've used pure O2 additions and found it did not help.

Even at 90% saturation, bacterial processes are running near maximum.

If you run an airstone at night, the first half of the night will actually lower the O2 levels since you have excess when the lights go out(more than 100% and all the aeration in thwe world will not help).

The only benefit I can see is that of added current from the aeration.

As far as why no pearling...................
Egeria should pearl if there is enough CO2/light/nutrients easily.
Water sprite should be covered like a champagne with bubbles.

Water change, clean the filter, prune trim etc, add nutrients back.
Check your readings. Don't trust them if something does not seem right.

Get your CO2 at 20-30ppm and keep it there for the entire day peroid. Check am and pm pH's and see if you are in this range.

clean bulb, reflector etc.
It's a small tank so this is not a big job.

Regards,
Tom Barr

[GaspingGurami]

[quote:7e97a603ba="geoffrey"]
I like to take this out for discussion and at the same time solicit some feedback. I too do not aerate my tank with air and I let my CO2 runs 24/7. I am seriously considering aeration in my tanks after photo-period. Reason being a good level of O2 from the air helps the nitrifying bacteria to work better converting NH3 to NO3. Particularly helpful in a high bio-loaded tank as mentioned by Choy and also, less prone to algae since NH3 is quickly converted to NO3. Like to know if anyone noticed a difference between doing it and not doing it. What's your take?[/quote:7e97a603ba]

Why don't you run an NH3 test first. I'm sure you, like many of us still have a kit like that somewhere, from the "fish-only" days. Chances are your NH3 would be zero, so no point aerating yr tank at night, there's no NH3 excess to convert.

Moreover, you'll be wasting your saturated O2 by aeration as the atmospheric air pumped into the tank has less O2 than your tank water.

I, OTOH, am trying to take off the airstone asap, but my plants are not cooperating.

[juggler]

[quote:5da1336c2c="hwchoy"]you got coral chips in your tank? what substrate are you using?[/quote:5da1336c2c]

Lawrence: are you using those ADA soil or what?

[geoffrey]

If you run an airstone at night, the first half of the night will actually lower the O2 levels since you have excess when the lights go out(more than 100% and all the aeration in thwe world will not help).

AND

Moreover, you'll be wasting your saturated O2 by aeration as the atmospheric air pumped into the tank has less O2 than your tank water.

Good points. Guess no need for aeration after all

BTW, Tom is right, Egeria and Water sprite should pearl like nobody's business unless something is seriously wrong.

[GaspingGurami]

[quote:9e2c254656="juggler"][quote:9e2c254656="hwchoy"]you got coral chips in your tank? what substrate are you using?[/quote:9e2c254656]

Lawrence: are you using those ADA soil or what?[/quote:9e2c254656]

Yes, I have some broken pieces of coral buried in the gravel somewhere. Not much, about 4-5 pieces of one-inch pieces. Somehow, couldn't find them so I can't remove them, but I don't think they'll make such a great difference to the pH. Or would they? With a kH of 3deg, My gH is 4deg.

I'm using only Lapis gravel 2 different mesh sizes, can't remember the grit no. They ought to be inert, I think.

On MC today, tore a ligament fishing yesterday so I have the time to observe the tank from dawn till lights up (at 2pm).

Noticed that with the solenoid off, water gets siphoned into the bubble counter up till the check valve. When power returns, this water gets pumped back into the tank. Now I think this is possibly where the Low pH is coming from.

After a day without Co2 yesterday, and a night of running the airstone, CO2 was down to 10ppm. Fishes were visibly happier being able to breathe easier.

One hour before lights on, I removed the airstone and ran 1 BPS CO2. Within 45 minutes, CO2 level has reached 25ppm, and the fishes were hypoxic. The weaker ones are at the surface.

I readied a pail of conditioned, well aerated water for the next part. Turned on both 36watts of lamps and lowered them without stands till level with the brace.

When lights came on, the shocked fishes sank to the bottom, still hypoxic. Told myself to observe for 15 minutes. If fishes still no improvement in condition, it means no photosynthesis going on, and must change water before all of them dies of excess CO2.

Within 10 minutes of lights on, fishes more relaxed. I also relaxed knowing that things are looking better as the minutes tick by. After 20 minutes, I put away the siphon. After 30 minutes, kept the pail of water. One hour after the lights came on, E. oriental started to send a stream of morse code in bubbles. After 2 hours, Cabomba is coated in a layer of bubbles that look like fairy dust, Riccia was starting to put out tiny pearls. Now 4 hours after lights on, A. nana is also blowing streams of bubbles.

Egeria and Ceratopteris make some pearls under their leaves.

I think the worst is over folks, thanks for all the advices and your interest in my problem. I'm grateful for all your support.

Just took a measure of pH: 6.4 with a kh of 4deg, CO2 is 47ppm! Shall I tweak with the needle valve? Oh heck, no. think I'll just leave it as it is for a couple of days.

[hwchoy]

you're getting phobic, finding problems where they don't exist.

the first thing you should do is to get the fish population down to where they commensurate with the water volume. For 20 litres I would suggest 6 fish.