• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

Plants never pearl / not looking too great

Tropical Simon

Seedling
Joined
17 Nov 2014
Messages
21
My tank has no CO2, its 200 litres with 60watts of light on for 6 hours a day. I am dosing it with 5ml of LUSH Max per week and most plants have root tablets under them. NitrIte and amonia is 0 and nitrAte is around 20.

I only have basic plants like vallis, echinodorus, a bit of hygro and some swords. The swords are beginning to get brown algae on the leaves and the rest of the plants aren't as healthy green as they were when I bought them.

From my specs and what I'm doing would you say I'm doing something wrong or could do something better?
 
My plants started pearling like crazy when I increased lighting. Tank is 180ltrs and I was running 2x39w for about 7hrs a day - no pearling whatsoever. Now I blast it with additional 2x39w for 3 hours a day and this is when they all start pearling. I struggle with some green dust algae though and lighting could one of the root causes so be careful with that. Also check your co2 level and distribution to make sure all plants have full access to it.
 
My tank has no CO2, its 200 litres with 60watts of light on for 6 hours a day
That can explain why you don't have pearling... it is not common in non-enriched tanks (at least never seen it in my low techs, just a light bubling a few times after some water changes)

The swords are beginning to get brown algae on the leaves and the rest of the plants aren't as healthy green as they were when I bought them
This has to be your concern... pearling is not what you have to focus on. Pearling is a nice side-effect you can have, that's all. It isn't an objective to reach.

My plants started pearling like crazy when I increased lighting. Tank is 180ltrs and I was running 2x39w for about 7hrs a day - no pearling whatsoever. Now I blast it with additional 2x39w for 3 hours a day and this is when they all start pearling. I struggle with some green dust algae though and lighting could one of the root causes so be careful with that
That's the risk of looking for pearling... actually it is quite easy to see pearling. High Co2, high light, high biomass... and you got it, but pearling doesn't mean healthy growing necessarily. I've had pearling and algae problems in my tanks at the same time.

As mention by Martin you should give us more details about your tank. Are plants adapting from emerged to submerged? Which filter do you have? How frequent and large are your water changes? How often do you clean your pipes, filter, tank? How is the flow in your tank? Pictures may help a lot, both of the tank and algae you have

Jordi
 
The pearling according to my observations "shows itself" when there is a lot of dissolved oxygen in the water, and the level of O2 is near or over 100% saturation point. Then all your fast growing plants should begin pearl. When you increase your light, the photosynthesis will go faster, and your plants will produce more O2. This will help increase the O2 level in the water, and if you have plenty of plants + strong lighting, then you O2 will reach the 100% saturation point quite fast during the photoperiod (and your plants begin to pearl). If you don't have enough plants + low light, then the O2 level will probably never get to saturation point.
 
New
The pearling according to my observations "shows itself" when there is a lot of dissolved oxygen in the water, and the level of O2 is near or over 100% saturation point.
This is not true at all. Pearling has nothing to do with O2 saturation.


This has to be your concern... pearling is not what you have to focus on. Pearling is a nice side-effect you can have, that's all. It isn't an objective to reach.
Correct.

The OP should focus on having healthy plants which will eliminate algal blooms.
Non CO2 enriched tanks will require more time and patience. It's a good idea to reduce the light intensity for a while as the plants make the adjustment to a submersed life.

Cheers,
 
I've always thought pearling was the oxygen produced during photosynthesis and unable to be dissolved in oxygen saturated water... So, how do pearling works in a tank?

Jordi
 
I've always thought pearling was the oxygen produced during photosynthesis and unable to be dissolved in oxygen saturated water... So, how do pearling works in a tank?

The rate at which O2 is produced by plants is faster than the rate at which it is absorbed in the tank wáter. You can still dissolve even more o2 after the wáter is saturated with it.
 
Do you mean it is just a matter of production and dissolution rate? Nothing to do with the pressure/amount of gas in the water column?

Jordi
 
Last edited:
The rate of dissolution is a function of things like preassure, temperature, gradient of concentration (O2 levels) between other things. But the main thing to see pearling is to have a big ammount of O2 production by the plants and a low ammount of degassing (small O2 gradient between leaves and water) as well as the right temperature..
 
So the ideal tank for pearling would be: A non surface agitation one (this lets O2 levels climb so its more difficult to dissolve more O2 into the water), with good co2 levels, high light and temperature as high as posible but not too high to degass a high co2 ammount or to damage plants. Also it would help if you live in the Alps for preassure. Not saying this is the ideal tank overall though, just for pearling.

As a side note: You might not have pearling in a very fast growing tank with perfect conditions if the surface agitation is high because you are degassing O2 and also because the high flow can dissolve the O2 generated by the plants faster.
 
Last edited:
I find my pearling increases when I increase surface agitation, which allows me to increase Co2.
 
Thats because plants photosynthesize faster with more CO2 so the O2 production increases. What I said before is with the premise of having the same CO2 ppm.
 
Hi all,
There is a lot of work in aquaculture on high levels of dissolved oxygen, partially because even in grossly polluted water you can get oxygen super-saturation, often when you get stratification in ponds under calm, warm, sunny conditions.

The sunlight stimulates algal photosynthesis and then it is a bit like boiling a kettle, as the water warms, oxygen comes out of solution as pearling.

You can get a situation where the upper water column is super-saturated with oxygen, but the lower levels are anoxic. If fish remain in the lower water column they will asphyxiate, so they move to the upper water column where thermal stress and "gas bubble disease" (from the gas super-saturated water) may also cause death.

If steps aren't taken to both mix and aerate the water column, and reduce the BOD, total fish kill will occur when the sun goes down and photosynthesis ceases.

There are some useful bits about dissolved oxygen in <"The Role of Dissolved Oxygen in Hard Clam Aquaculture">.

cheers Darrel
 
Back
Top