1.8 watt/gal with nice red plants

[THE V]

Fun little thread Tom.

I'm just going to toss in a little monkeywrench into the whole thing just to be a brat. :silly:

PAR is only a rough estimate how much light is available for the plants to use. It does not always correlate to what the plant actually needs. The actual usable light varies by species and even cultivar. The major flaw is that the meters don't measure the different spectrum's that make up PAR. Some species like more red light while others are more partial to blue. So even though the PAR measurement says that the light meets the requirements for the plant, in reality it is still a gamble. I will however give in an say that PAR is much better than any other commonly used measurement.

The whole watt per gallon rule has always been quite silly in my opinion. The plants don't care how many gallons your tank is. All that they care about is the combination of spectrum, intensity, and duration of the light. On smaller tanks and beginners it can help them at least grow some plants.

Couple things that I'd like to add after doing a little reading and experimenting around.

1. If you don't want to run CO2 you can decrease the light intensity but increase the duration and achieve increased plant growth.

This is an old greenhouse trick. In the winter when it is cold outside there is very little air motion in a GH between the inside and outside. You can install CO2 burners but they are a hazard to anyone working in the GH. So one trick is to put in lower power lights but to let them run longer. The plants have very similar daily CO2 needs but they eat it over a longer period. A longer period = more time for CO2 to diffuse into the GH through the pads and other holes. In the aquarium the longer the duration of the light the more time for CO2 to diffuse into the water. I'm currently running 20 hours in the GH and 14 hours on my lower light tanks.

2. Check your tap waters nutrient levels first before fertilizing. These are generally available from you local water district or if you are on a well its a $50-$75 test (at an agricultural testing facility). Too much of almost all nutrients equal toxicity. I've got so much B and Mg salts in the ground water at work that when I tested out some Egeria densa in the water it was fried in a few days (we have a service that brings in drinking water).

Now if you want some fun the next topic could be light needs of plants at different stages of life... Now there's a nice simple topic :uhoh:

 

[EileenH]

I have all low light plants in my tanks, Black sand and black Eco-complete. No Co2 and floua sun bulbs nothing special. My plants grow really well. My biggest tank is a 55 gal. with pool filter sand and 2 15 watt reg lights. I put plant tabs in the sand for the plants and they are growing really well. I know that co2 is expensive and my friend has low-light and no co2 and aqua sun bulbs in her tank so I wanted to do low key. You can find some really nice low light plants that grow well with out all the expense. I just wanted to put this out their for someone that wanted a nice planted tank with out spending alot. My lights are all on a timer and are on for 9 hours a day.

 

[plantbrain]

PAR is only a rough estimate how much light is available for the plants to use. It does not always correlate to what the plant actually needs. The actual usable light varies by species and even cultivar. The major flaw is that the meters don't measure the different spectrum's that make up PAR. Some species like more red light while others are more partial to blue. So even though the PAR measurement says that the light meets the requirements for the plant, in reality it is still a gamble. I will however give in an say that PAR is much better than any other commonly used measurement.

I am aware of the trade offs, and the preference for more % red or blue is also seasonal, and depends greatly on the life stage of the plant, careful, there's plenty of assumption to go around as you say at the end there:
If you know of a meter that will give the entire curve, is water proof, under 300-500$, what the heck, let's go up to 1000$, please do tell?

Yea, it's really a trade off, but at some point, when comparing things, we have to make some assumptions.

Since plants can and do adapt well to different light, they do this in nature and certainly in artificial light, this means less with respect to broad band PAR meters. Fake light is stable and and changes much less than sunlight once you set up the tank and add plants/bulbs etc. There are shifts, but not as much as we might think that occur in nature.

So for practical reasons, a PAR meter is a huge leap forward vs any of the alternatives and some what reasonable for the cost trade offs and very reasonable given that not all plants have the same preference for different spectral outputs in their vegetative growth state.

So PAR makes much more sense for us unless we desire to get specific about each plant species and test and measure it's relative growth rates with different spectral compositions, fine if it is for say Tomato or Saffron, any larger commercial crops , but not for obscure aquatic plants.

Folks are quick to critique PAR without applying it and seeing what those trade offs really are. What might be applicable for Tomato research, might have little bearing on 400 different species in a community.

It's an old argument Botantist have long had.

The whole watt per gallon rule has always been quite silly in my opinion. The plants don't care how many gallons your tank is. All that they care about is the combination of spectrum, intensity, and duration of the light. On smaller tanks and beginners it can help them at least grow some plants.

W/gal always worked well for me, but when I wondered why ADA's lighting was so high and the tanks gre at slower rates, I compared them, and the PAR was 1/2 that of the prediction. W/gal still worked, but it was much less than we predicted.

This made the ADA system much more understandable and why it was more manageable for many.

If we are going to compare light amongst aquarist, it makes for the best solution.

quote]
Couple things that I'd like to add after doing a little reading and experimenting around.

1. If you don't want to run CO2 you can decrease the light intensity but increase the duration and achieve increased plant growth.
[/quote]

Well, you can actually get away with less light if you use CO2.
Ole and Troels explains it well here:
http://www.tropica.com/go.asp?article=142

Read the entire article.
It's a good one on allocation of resources that most aquarist have little understanding about and makes a good reference/easier to read than more technical stuff not for hobbyist.

This is an old greenhouse trick. In the winter when it is cold outside there is very little air motion in a GH between the inside and outside. You can install CO2 burners but they are a hazard to anyone working in the GH. So one trick is to put in lower power lights but to let them run longer. The plants have very similar daily CO2 needs but they eat it over a longer period. A longer period = more time for CO2 to diffuse into the GH through the pads and other holes. In the aquarium the longer the duration of the light the more time for CO2 to diffuse into the water. I'm currently running 20 hours in the GH and 14 hours on my lower light tanks.

Well CO2 demand is obviously less since light drives CO2 uptale.
Less light= less CO2 demand. You can make up for it some with longer duration time, but if add CO2, this amount of LCP will decrease.

2. Check your tap waters nutrient levels first before fertilizing. These are generally available from you local water district or if you are on a well its a $50-$75 test (at an agricultural testing facility). Too much of almost all nutrients equal toxicity. I've got so much B and Mg salts in the ground water at work that when I tested out some Egeria densa in the water it was fried in a few days (we have a service that brings in drinking water).

Too much Mg, really, and how much is too much Mg?
B is another story, but not been hardly much with any tap I've used.

We have 52ppm of Mg at the lab here from Davis CA.
That's higher than any tap I've seen, we have many vaults full of E densa, one of the main aqautic weeds here in CA.

Still, I view tap more as a source of nutrients, than toxicity, rarely has it been an issue, copper ina coupoel ofi cases, that's about it, a few well users with high metals or Na+ levels etc, but overall, tap water is pretty good in the USA. Europe and some other palces, not so hot, higher NO3 etc. Private wells are a case by case issue.

Now if you want some fun the next topic could be light needs of plants at different stages of life... Now there's a nice simple topic :uhoh:

Yes, but since we only grow aquatic plants(most of us, 99.99%) in one life stage, the vegetative, not much of an issue.

Regards,
Tom Barr

 

[plantbrain]

I have all low light plants in my tanks, Black sand and black Eco-complete. No Co2 and floua sun bulbs nothing special. My plants grow really well. My biggest tank is a 55 gal. with pool filter sand and 2 15 watt reg lights. I put plant tabs in the sand for the plants and they are growing really well. I know that co2 is expensive and my friend has low-light and no co2 and aqua sun bulbs in her tank so I wanted to do low key. You can find some really nice low light plants that grow well with out all the expense. I just wanted to put this out their for someone that wanted a nice planted tank with out spending alot. My lights are all on a timer and are on for 9 hours a day.

Non CO2 method are excellent also.
Much more a sustainable approach to aquarium keeping if not the THE most sustainable. No water changes for some of my tanks for 2-3 years at a time and they still look good and grow plants well.

There are trade offs, I could not have the same display in the 1st post without CO2..........for example, but I might not have that goal, it might be something like this instead which is still a handsome tank:

Many are too impatient and think more, is better.
More $, faster and higher power is better.

Well, it's more work, that's one thing I can certainly say:FIREdevil:
Better? Depends on who you ask and their goals. There's a strong CO2 bias on the web forums. Put of the facts, get them straight, then folks can distort them however they deem fit


Regards,
Tom Barr

 

[THE V]

:evil_lol: No botanist I know can resist any hint of a PAR debate. Thanks for the entertainment and good info.

Mg is generally not observed as any damage to the leaves so it is not often discussed. Of course I've only seen it in vegetables. The only way to detect it is by tissue sampling. Generally the plant looks perfectly healthy but grows very slowly. It's rare but I found this one out the hard way because the well my company has at Davis is extremely high levels of Mg (the carbonate and Cl- was high as well) My company just forked out some major cash for three 100,000 gallon tanks and two large RO systems to clean it up.

I was impressed by the C02 & Light link. The concepts are nicely summarized.