High Light vs Photoperiod vs distance (PAR)

[sundragon]

Originally Posted by foxfish

I do find it interesting how you guys pay so much attention to light as there is a very different perspective from where I come from ...

I am pumping CO2 into the tank with great results save the hair grass - I don't want to make a huge change in chemistry or set up just enough of a push to make that grow better.

Originally Posted by Hoppy

If you enjoy all of that work, you will also enjoy the rewards of having a good high light tank.

I don't want a lot more work

I think there may have been some confusion.

I misread that 70 micromoles should be enough to grow hair grass so instead of having the burst I thought an option was to keep the 4 banks open and keep it at 70 micromoles. It would be easier than dropping the light from 33 inches to 24 inches.

I now realize you said 35-40 should be enough so lowering the lights is a better solution. I am just a bit cautious of dropping the lights 9 inches from 33 to 24 inches - It sounded like a huge increase in light.

When I drop the light should I do away with the burst all together?

[sundragon]

Originally Posted by foxfish

Here is a nice example of a 100cm tank lit by two T5s approx 40cm above the water, light duration is 6 hours a day.
The tank belongs to Mark Evans and just made Rank 137 IAPLC entry.
We have lots of similar tanks on our forum using 2 x T5 or LED..

beautiful tank - I would love to know how deep it is - my tank is 21" deep and I have a lot of shading plants so I may need a bit more light penetration.

[houseofcards]

Originally Posted by foxfish

Here is a nice example of a 100cm tank lit by two T5s approx 40cm above the water, light duration is 6 hours a day.
The tank belongs to Mark Evans and just made Rank 137 IAPLC entry.
We have lots of similar tanks on our forum using 2 x T5 or LED..

I've seen some of Mark Evans stuff, excellent scaper and photographer, but he really is a professional so hard to compare what he does to a typical planted hobbyist here. His knowledge and dedication far outweighs IMO difference in light, etc. That tank looks longer than 100cm it looks like a 120cm. Also most of Mark's stuff that I used to see had a MH component to it. Are you sure there wasn't any other light on that setup besides the two T5 during the grow out.

[james1542]

Originally Posted by foxfish

Here is a nice example of a 100cm tank lit by two T5s approx 40cm above the water, light duration is 6 hours a day.
The tank belongs to Mark Evans and just made Rank 137 IAPLC entry.
We have lots of similar tanks on our forum using 2 x T5 or LED..

Here is an example of what you are not "supposed to" do(38 cm cube):


That is a 70W HQI metal halide about 45 cm from the substrate on for 1 + 7 hrs a day. I run NO CO2, for more than a year the only time I had algae is when I started using tap water-stopped using tap water and the algae is not growing any more. The only ferts are Osmocoat + in the substrate (fluval shrimp stratum). Some plants are museum specimens in my tank (erios) and sure I could grow the plants 3x faster (Yay for pruning and replanting every week), but it is really nice to look at, and many plants such as chain swords, swords, mosses, rotala looking stuff, are doing great.

[sundragon]

I upped the CO2 by 1bps and set the Hydor Koralia to run 24/7 instead of when the lights are out. The Hydor is set to churn the water and push it back to the filter intake across the back of the tank.

That should increase the CO2 and increase the flow

I am tempted to just leave it at that and see what happens in a week. Then lower the lights from 33 to 29 inches and wait a week. If everything's okay - I'll lower it to 24 inches from the substrate.

Currently I have 8 hours of light, (5 hours 2x T5HO and 3 hours 4xT5 HO) - no algae.

Should I kill the 3 hour burst and keep it to 2x T5HO or just reduce the burst?

[james1542]

The increased flow should help a lot. waiting and seeing can't hurt. If you currently have no algae problems, why would you try to cut your light even more? It's good to take things cautiously so you can figure out why they happened, but remember you do know how to defeat BBA if it comes back. I'm a fan of really high light, but I'm a miser with my ferts. You can have all the light in the world and algae will not grow if there are no ferts in the water. Plants can use the ferts much more rapidly than the algae can (although algae can crack out nitrogen that the plants cannot), and plants can use the light much more efficiently than algae can that is why plants can do fine on a 2 hour photo period if it's bright enough but algae will suffer. The best photoperiod for algae would be 24 hours on.

[Hoppy]

Originally Posted by james1542

The increased flow should help a lot. waiting and seeing can't hurt. If you currently have no algae problems, why would you try to cut your light even more? It's good to take things cautiously so you can figure out why they happened, but remember you do know how to defeat BBA if it comes back. I'm a fan of really high light, but I'm a miser with my ferts. You can have all the light in the world and algae will not grow if there are no ferts in the water. Plants can use the ferts much more rapidly than the algae can (although algae can crack out nitrogen that the plants cannot), and plants can use the light much more efficiently than algae can that is why plants can do fine on a 2 hour photo period if it's bright enough but algae will suffer. The best photoperiod for algae would be 24 hours on.

With high light and unhealthy plants you will get algae even if there are no measurable nutrients in the water. Algae consume minute amounts of nutrients, and are able to get them where plants are starving for lack of nutrients. It is healthy plants growing as fast as the light intensity is driving them to grow that tends to keep algae away. It isn't a competition for limited nutrients, but exactly what it is seems to be a mystery.

[Hoppy]

Originally Posted by sundragon

I don't want a lot more work

High light always means a lot of work, compared to low light.

I think there may have been some confusion.

I misread that 70 micromoles should be enough to grow hair grass so instead of having the burst I thought an option was to keep the 4 banks open and keep it at 70 micromoles. It would be easier than dropping the light from 33 inches to 24 inches.

I now realize you said 35-40 should be enough so lowering the lights is a better solution. I am just a bit cautious of dropping the lights 9 inches from 33 to 24 inches - It sounded like a huge increase in light.

When I drop the light should I do away with the burst all together?

What I posted is, "You can see, from that chart, that at 33" you are getting about 70 micromols of PAR, which is more than enough light to grow hairgrass. If you were to use just an adjacent pair of bulbs you would get about half of that, or 35 micromols, which might be too little light. But, lower the light to about 22-24 inches from the substrate and you should have about 45-50 micromols of PAR at the substrate from the two bulbs. That is plenty of light for hairgrass, and based on the charts in the manual, the light would be adequately uniform over the whole substrate." This means, with all 4 bulbs on, and the light 33 inches from the substrate, you get about 70 micromols of PAR, which is plenty of light for hairgrass. If you want to use only two bulbs, you can lower the light to 23-24 inches from the substrate and get 45-50 micromols of PAR, which is still very likely to be enough light for hairgrass. If you don't mind using all 4 bulbs for the whole photoperiod, just leave it at 33 inches and run all 4 bulbs for the whole photoperiod for 70 micromols of PAR.

[houseofcards]

Originally Posted by foxfish

Light causes algae, C02 grows plants! 2 x T5 is more than adequate to get a lush growth of any plant at that depth of water,
You need to get more gas down to the substrate.

General statements like this are just IMO incorrect and misleading. First off light grows plants as well, we can have too little at times. If the plants are growing slowly then sometimes a little extra light could lead to better organic uptake, better growth and a cleaner tank. This extra light might be in the form of a 1-2 hour burst that might have a more positive aspect on plant growth than a negative aspect on algae. It really depends on the setup,

Also the comment about the 2 x T5 being enough light for that depth was made before even knowing what kind of T5 the OP was using. As we know now this varies tremendously by model/manuf.

[foxfish]

OK then I am sorry if I made a misleading post! I will get back in my basket!!
I didn't really think for one second I could convince the hard core posters away from the general forum beliefs anyway.
And sorry about quoting Marks tank as a 100cm it is in fact a 120cm!
Limey out......
Incidentally I grew this scape myself with 2 x T5 on for 6 hours a day, note how the glosso actually grows downward & even the plants below the log grew as vigorously as he plant on top of the log...
http://www.plantedtank.net/forums/sh...d.php?t=127131

[houseofcards]

Actually I think most here agree that less light is usually better for many. In fact one of the more knowledgeable and well-known members here I'm pretty sure links that Tropica study you linked all the time.

I just don't agree with generalized, sweeping statements when it comes to home aquaria. Tanks to me are not controlled science experiments. There are simply to many variables tank to tank, light to light, substrate to substrate, etc. I do believe the Evans tank used MH lighting in addition to the T5, but I could be wrong.

[sundragon]

Originally Posted by foxfish

OK then I am sorry if I made a misleading post! I will get back in my basket!!
I didn't really think for one second I could convince the hard core posters away from the general forum beliefs anyway.
And sorry about quoting Marks tank as a 100cm it is in fact a 120cm!
Limey out......
Incidentally I grew this scape myself with 2 x T5 on for 6 hours a day, note how the glosso actually grows downward & even the plants below the log grew as vigorously as he plant on top of the log...
http://www.plantedtank.net/forums/sh...d.php?t=127131

I actually think this is an amazing tank - I appreciate your input or I wouldn't have asked the question in the first place.

There are many factors and I focused on light because everything else seems to be growing well save the hair grass.

As for light, I'm using medium-low light for 5 hours and medium-high for 3. I realized that my lights were too close and even after pulling them back it took a long time to get the algae under control (5-6 months). I have been told that I have a deep tank and the taller stemmed plants can decrease the light getting to the substrate so I posted my question here because most of you have more experience.

I have two questions about your tank? How deep is the tank and how far are your lights from substrate?

[sundragon]

Originally Posted by Hoppy

High light always means a lot of work, compared to low light.


What I posted is, "You can see, from that chart, that at 33" you are getting about 70 micromols of PAR, which is more than enough light to grow hairgrass. If you were to use just an adjacent pair of bulbs you would get about half of that, or 35 micromols, which might be too little light. But, lower the light to about 22-24 inches from the substrate and you should have about 45-50 micromols of PAR at the substrate from the two bulbs. That is plenty of light for hairgrass, and based on the charts in the manual, the light would be adequately uniform over the whole substrate." This means, with all 4 bulbs on, and the light 33 inches from the substrate, you get about 70 micromols of PAR, which is plenty of light for hairgrass. If you want to use only two bulbs, you can lower the light to 23-24 inches from the substrate and get 45-50 micromols of PAR, which is still very likely to be enough light for hairgrass. If you don't mind using all 4 bulbs for the whole photoperiod, just leave it at 33 inches and run all 4 bulbs for the whole photoperiod for 70 micromols of PAR.

Thanks Hoppy!
I appreciate you explaining it this way - will gradually move towards dropping the light and reducing the burst now that I've upped the flow and CO2.

[Hoppy]

Originally Posted by houseofcards

General statements like this are just IMO incorrect and misleading. First off light grows plants as well, we can have too little at times. If the plants are growing slowly then sometimes a little extra light could lead to better organic uptake, better growth and a cleaner tank. This extra light might be in the form of a 1-2 hour burst that might have a more positive aspect on plant growth than a negative aspect on algae. It really depends on the setup,

Also the comment about the 2 x T5 being enough light for that depth was made before even knowing what kind of T5 the OP was using. As we know now this varies tremendously by model/manuf.

It seems to me that alternative to giving specific advice is to say, "sorry, but your tank is different from all others, so you are just going to have to figure it all out for yourself. There are just too many variables for any of us to be able to offer you any help. But, don't ask me to define all of those variables, because only God knows them."

Everyone's advice here has some probability of being wrong. That is just a given.

[houseofcards]

Originally Posted by Hoppy

It seems to me that alternative to giving specific advice is to say, "sorry, but your tank is different from all others, so you are just going to have to figure it all out for yourself. There are just too many variables for any of us to be able to offer you any help. But, don't ask me to define all of those variables, because only God knows them."

Everyone's advice here has some probability of being wrong. That is just a given.

Are you being sarcastic, I honestly don't know, but giving specific narrow, advise about a setup without knowing anything about that setup really doesn't help IMO. What helps its asking questions about a setup and then offering broader advise and the OP or whoever can decide if that fits his/her situation.