surface Agitation & CO2

[dingweding]

I read here in planted tank, i still should have surface agitation.

in my tank, there is no water surface movement, thus sometimes there is oily film on the water surface.

I am thinking to raise the outlet of the filter out of water, thus the water can flow down and hit the surface, generate many bubble downwards.

however, i am worried this will increase the escape of CO2.

any suggestions? thanks

 

[hanno]

Hi Dingweding,

Actually I have a tank with a very strong current, also with a gentle surface agitation. But I also have good CO2. Two years ago I had a tank without, resulting in having this film sometimes. Both works and you can achieve good CO2 levels by dissolving more CO2 , if you have a strong surface agitation.
The main problem to you is the oily film, right? - You can avoid this also by feeding less. That was my experience. Fish need much less and much less often food than we think. Always look for a healthy shape, but you can take into account that most fish get some food out of the tank by algae, plants and detritus.

Cheers,
Hanno

 

[dingweding]

thanks for the answer, actually i have quite a lot problems :-(

 

[dingweding]

i had 2 planted tank b4. all the plant grow quite well, even with diy co2, and no dose. However,

After i moved house, i set up a new 80L tank, no fish, just 3 snail and a few shrimps.
3 x 24w light, the light is on 5hours , off 2 hours , then on 5 hours again.

bottoled CO2, about 1 bubble per second with glass disffuser,
however, no sign of pearling, at first a few days, the plants grow very fast evn no pearling.

Then, some fragile plants become rotten, my HC turn yellow. some other plants'new leaves become narrow and long, and the edge of some leaves become curl up?


I do not know is it too much fertiliser or too little?

i dose EI 1/8 tsp KNO3 2x a week
1/32 tsp KH2PO4 2x a week
1/32 tsp K2SO4 2x a week
1/32 tsp traces 2x a week

the tank is 80L, i know i should does normally 3 times , but i only change 20% water every week, as there are CRS shrimp in the tank 50% water change is too much for them.

so will this end up too much fertiliser ? or i should put more fertiliser?

or should i increase CO2?

 

[dingweding]

there are some brown algae, which i know is common for new tank.

i also notice some fuzzy algae grow on my moss, and spread fast, made my Xmass quite ugly.

 

[Philosophos]

My guess is you might be over fertilizing, given how little water you're changing. Try two 30% water changes a week; it ends up being cumulatively about 50%.

Your light is extremely high, try running 2x24. Get compressed CO2 to go with it. DIY CO2 is only good up to around 1.5-2wpg, and even that can benefit from Excel.

I'm not sure about your fert dosing. I work by weight and mL in liquid. If it's standard EI ratios, then you should be fine.

-Philosophos

 

[dingweding]

i do use compressed co2.

now i was confused. some ppl said why the plants has narrow leave, and look stunt, some even rotten away, this is a sign of nutriention deficiency. As the light is high, the plants need more nutrition to grow. once it runs out, they will die.

or is it beacuse too much fert?

last year in my old tank, i never dose, the plant goes quite well.

 

[Philosophos]

Sorry, thought you had DIY for some reason.

Nutrients can go far higher than what EI suggests before they poison plants. The problem is if you're running long term with 2/3 EI dosing and 20% water changes, you're going to end up with 2x the dose:

100-20%-20%-20% = 51.2 -That's 3 weeks for the equivalent of a 50% change

3*2/3 = 2

While 2x the dose may not necessarily be toxic, it certainly isn't limiting. So then, there's more chance of toxicity than deficiency.

More likely is not enough CO2. Just having compressed CO2 doesn't mean that enough is getting in the tank, or that it is distributed well enough. Turn your CO2 up, and watch your fish closely. Increase it slowly, and work on getting it distributed throughout the tank.

Even with incredibly good CO2 distribution and proper nutrients, 72w over 80L is a lot. I say this because you have it in three strips, which is going to create very good distribution. Your PAR levels are going to be higher than someone using a single CF of equivalent wattage.

How was your old tank set up? If you had far less light, then food and water changes alone may have been enough to supply nutrients.

-Philosophos

 

[dingweding]

the old tank just have diy co2, also quite high light, no dose , but plants go very well, but that is last year.

 

[VaughnH]

It would help a lot if you slowed the tank down, by reducing the light intensity. 24 watt lights on that size tank sounds like T5HO lights to me. Your tank is relatively short, so the lights are close to the substrate, giving even higher intensity than if they were 18-20 inches from the substrate. I would be tempted to run a single T5HO light, and try to get the plants growing in good health, with few algae problems. And, after that I would consider turning on a second 24 watt bulb.

Tom has pointed out many times that most problems we run into end up being about not having good CO2 concentration and distribution in the water, along with having so much light there isn't any "slack" for us to be off a bit with CO2, or fertilizing. It would be wise to assume that is your problem too.

 

[dingweding]

Now i do suspect that is cuased by too much fertilizer, the more i more i dose, the more they look stunt and rotten. i increase the CO2, reduce the light, add water surface agitation, all no response.

But at last year, i do not know any thing about dosing, i never put any fertiziler , the plants goes , now even the hardy plants stop going.

another reason i suspect the fert is, i used the changed water to water my house plant, some plants died as well. how shocking.

 

[Philosophos]

I'd look deeper in to your fertilization of choice. Proper fert ratios shouldn't cause problems at 5x the recommended levels for your plants. Maybe for the fish, but not the plants. That being said, what you've got in your fertilizers may not be at amounts balanced for even 2x the recommended amount. Copper is commonly (and often incorrectly) blamed, though I've learned to suspect sodium first.

-Philosophos

 

[dingweding]

just test my tank water, as London water is very hard.

tap water PH is 7.7 , GH 17, KH 11, NO3 50ppm
tank water PH 7.4, GH 12, KH 10, NO3 0ppm

i was told plant can not do well in such hard water, will this be the problem?

 

[Tom Barr]

If you add CO2, it's not an issue(KH).
GH is just nutrients, eg Ca and Mg.

CO2 is why the plants are not pearling, looking good etc.
Focus there.

Also, there is a large contingent of folks in London that are in the UKAPS. They are familiar with the tap water. In many places in Europe, higher NO3 in the ground water is common after centuries of agriculture. PO4 as well.

If you did say 50% weekly water changes, dosed K2SO4 in place of KNO3, then it would target the right amount.

2x 24w T5's lights should be plenty for most anything you'd ever want to grow on an 80 liter tank.

Focus very strongly on light and CO2, the nutrients are rather easy.

Here's one of my old tanks when I lived in a place that had hard water(Santa Barbara CA):

GH was 24 degrees, the KH was 11.

So.........

Regards,
Tom Barr

 

[Tom Barr]

What likely is occurring is when you add nutrients, the plants are not limiting, so it rules them out as a limiting factor. This leaves light or CO2, you plenty of light on an 80 liter tank.

So.........now you are left with one variable: CO2.

Nutrients (excess) do not cause melting, algae poor growth etc.

Otherwise I would have melted plants as well, as well as most folks in the UK. Clearly, this is not the case.

You might find more support and resolve at Welcome To The UK Aquatic Plant Society
They can clear up the myths and notions many of us have when looking at these issues.

Not easy figuring out what to believe.
So if you find some folks doing well locally, it might help you more so.

I can only say we know, independent on any other factors, that the nutrients and hard KH's are not the issue/s. Nor is light in your case, there might be other things in the tap, but activated carbon would address 99% of those and the most likely culprit is CO2 based on everything you have said.

UKAPS will tell you a similar thing I'd suspect.

More light = more CO2= more nutrients.
Too little of any of these= not good
Too much light makes balancing the other two much harder.

I'd stick with 2x 24W and tweak CO2, use Eas Carb for a couple of months, dose K2SO4, maybe 1.25mls 2x a week or so, do 50% weekly water change, add KH2PO4, maybe 4x less the amount of the K2SO4(1.25mls or 1/4 teaspoon), Traces at 5mls 2-3x a week.

I think CO2 is going to be your nemesis. Focus there and be careful with it, do this slowly. Easy carb will help while you adjust this.


Regards,
Tom Barr

 

[dingweding]

Thanks a lot, Tom, i will give it a try.

 

[dingweding]

in my filter. i put a bag of activated carbon a few weeks ago, i think it might get rid of all my fertiliser?

meanwhile, there is a bag of peat in my fiter, which was left nearly half year ago when i use it to decrease PH.

last night, i discard the carbon, and put a new bag of peat to replace the old one.

any suggestions?