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Black type algae stunting growth...advice required.
- Thread starter MDP91
- Start date
MDP91
Member
On a slight side note I didn't think 216watts of light for a 450lire aquarium was classed as high light?
Hi,
As discussed in many threads here, the traditional way of assessing low, medium and high light is completely flawed. It was OK way back when the only type of lights available were the much lower output T8, however, with the advent of higher output T5 it was discovered that the watts per gallon method does not work.
Additionally, as we often mention, many hobbyists fret over the fact that their light may not penetrate to the lower parts of the tank, when in fact the plants do not really care about that. What they care about is gas exchange. They need a good supply of CO2 in order to produce the food they need to live. They also need Oxygen to burn the food they manage to produce. These commodities are always in short supply in large tanks.
Plants use the visible spectrum to generate the electricity necessary to strip CO2 of Carbon so that Carbohydrates can be manufactured.
The energy of the light is referred to as Photosynthetically Active Radiation, or PAR.
This energy, supplied in an amount commensurate with the available supply of CO2, is summarized on this chart.
You can see how much margin of error is built into the much lower T8 bulbs.
The key to determining Low, Medium and High is the distance the leaf is from the bulb. Generally, we use the distance the substrate is from the bulb as a standard reference. Using multiple bulbs, as indicated on the charts magnifies the PAR.
If you consistently operate in the high pink to yellow zone without having excellent CO2 you will usually incur algal blooms.
Even if you are in the blue zone, if your CO2 techniques are particularly poor this can result in blooms.
Cheers,
MDP91
Member
Thank you again for the reply, although I'm struggling to work out my light par based on my setup using that chart 
Well, we know the number of T5 bulbs you are using, to that tells us which curve to use and what multiplier to apply, but you haven't actually told us what the distance is from the bulb to the substrate so we cannot determine where the curve-to-distance intersection is.Thank you again for the reply, although I'm struggling to work out my light par based on my setup using that chart
Cheers,
MDP91
Member
My lights are about 20inches from the substrate.
Edvet
Member
According the chart: 1 x T5 HO at 20 inches 60-70 par, times 4 is 240-280 par 😱 (one is already medium light)
That qualifies as (ultra) high ( megaton) light😵
That qualifies as (ultra) high ( megaton) light😵
MDP91
Member
I've seen people running more lights than I have only smaller tanks though and not had issues?
Hmmmmm, if I ran only one light the tank would be very dim 🙁
Hmmmmm, if I ran only one light the tank would be very dim 🙁
Edvet
Member
Wel the plants disagree sadly. Can you alter the height, doubling it will lower the amounts by 4x
MDP91
Member
Thank you, I think I'll keep my newly increased Co2 and knock two bulbs off. They work on a two bulb per plug system as its an iquatic juwel replacement system.
Hi
It's always a mistake to isolate any single element of your tank and compare it to other tanks having that same element. Plant health is a derivative of many variables in a tank. Suppose that other person had better CO2 than you do? That would easily explain their success and your failure. CO2 is much easier to implement in a smaller tank. Other variables such as flow and distribution play a role, as does the ability of the plants to adapt to higher levels of stress as the tank matures and as the plants develop, so you could be comparing someone's mature and developed tank to your lesser developed tank.
At some point high stress levels and high growth rates will be achievable, but you have to be able to get there from here. For every person that insists that they use so many megawatts and achieve success there will be a hundred who tried the same and vaporized their plants into oblivion. Each element has to be assessed within the context of the whole.
Cheers,
It's always a mistake to isolate any single element of your tank and compare it to other tanks having that same element. Plant health is a derivative of many variables in a tank. Suppose that other person had better CO2 than you do? That would easily explain their success and your failure. CO2 is much easier to implement in a smaller tank. Other variables such as flow and distribution play a role, as does the ability of the plants to adapt to higher levels of stress as the tank matures and as the plants develop, so you could be comparing someone's mature and developed tank to your lesser developed tank.
At some point high stress levels and high growth rates will be achievable, but you have to be able to get there from here. For every person that insists that they use so many megawatts and achieve success there will be a hundred who tried the same and vaporized their plants into oblivion. Each element has to be assessed within the context of the whole.
Cheers,
MDP91
Member
Thank you, that makes perfect sense. Lots to learn.
I have knocked off two of my 54W T5 Bulbs and increased my CO2 for the time being to see if that will gradually bring my plants back to health.
I have knocked off two of my 54W T5 Bulbs and increased my CO2 for the time being to see if that will gradually bring my plants back to health.
Hi,
Yes, reducing the light will reduce the stress considerably.
Also, to reiterate what the other posters have mentioned, the way in which you distribute your flow is very important. I think you had asked how is it is that in order to get your DC green your fish were experiencing hypercapnia. That is an early indication that your distribution methods of CO2 are suspect. When fish suffer hypercapnia at the same time that the plants suffer CO2 deficiency this means that the CO2 is dissolves in an area where the fish are, but does not have a significant presence where the plants are located. This is a very common occurrence and is fixed by paying more attention to the placement and orientation of your filter return outlets. If you can provide a photo of the plumbing in the tank whcih shows the filter oputlets and whioch shows the injection method, we might be able to help you fine tune them.
Cheers,
MDP91
Member
Thank you, I seem to have solved this issue , I have adjusted my circulation pump and filter outflows and now get a nice circular motion through the tank. DC is a lime green on lights on and remains for the photoperiod.
Only have the one HO T5 running over the tank to let all the plants recover.
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