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High Light vs Photoperiod vs distance (PAR)

9K views 36 replies 8 participants last post by  james1542 
#1 · (Edited)
How do I get my lush hairgrass back?


So I've been running my tank for about 8 months:

I had an outbreak of hair algae when I first set up and realized my lights were waaaay too close to the surface. I hiked them up and now they are 33 inches from the substrate and 16 inches from the surface of the water. I also did a blackout that wiped out the algae (along with my tiger lotuses)

I then got the ferts wrong and had a nice outbreak of BBA which was a pain to get rid of, but is nearly non existent after a month thanks to Excel and regular water changes.

57G 36x18x21"

Lighting
I have 4x 39W T5 HO bulbs running in two separate banks.
I currently run one bank of light for a total of 6 hours. (14:00-20:00).
I run the second bank of light for 5 hours (17:00-22:00).
78W for 8 hours total, of which 156W for 3 hours (when they overlap 17:00 - 20:00).

CO2
I run pressurized CO2, and ferts - everything grows really well - The reds are starting to pop on the plants that are near the surface and staurogyne repens is growing like a weed but the hairgrass...

The hairgrass is alive, but quite thin compared to when the light was closer (When I set up the tank).
I do not want to have an algae outbreak again so I'm toying with dropping the light an inch to increase the PAR value at the substrate surface, alternatively, I can increase the photo period or the amount of light

I've read that dwarf hairgrass likes 2WPG or more. That being said, I know to focus on PAR vs WPG as a measure of effective light.

So what's the recommendation? I won't do any drastic changes - one nudge and wait, another nudge and wait...
 
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#3 ·
Nice looking tank, is that A. Viejita on the right side on D31-what strain is that?

I'm no expert when it comes to ferts, light and CO2, but in my opinion.., Looking at your before and after, I think it's safe to say you don't have enough light for a carpeting plant like that. Also, I would not be fond of the amount of stray light you are getting with your light so high up. I mean how can you enjoy your tank with 4 bulbs of T5 HO blasting you in the eyes!

My suggesting: move it back close enough to the tank where viewing is enjoyable, and get some floaters like frogbit or dwarf water lettuce to shade out some of the light. Also keep the photoperiod to 8 hours or less. In my mind when I think of algae and light, the longer the photoperiod the better the algae will do. I'd rather have high lighting for a short time, than weaker lighting over a longer period. Your plants will appreciate the high light, they are more efficient than the algae and only need a few hours of it a day to thrive. Furthermore, I don't see any harm in having a few photoperiods a day, and I suspect it would benefit your plants, I understand your trying to replicate nature, but there is lots of algae out in nature too and lets face the facts, most natural systems don't have injected CO2! I set my photoperiod to be on only when I'm going to home to enjoy it, plus I'd just have all 4 bulbs on, I don't think the plants really care if it ramps up from 2 to 4 bulbs.
 
#24 ·
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.
 
#5 ·
I was too chicken to move the lights lower so just increased the photoperiod by half an hour every couple weeks. My hairgrass, Blyxa and P. Kawagoeanum responded beautifully to an 8 hour photoperiod. Your choice I think.
 
#6 ·
Thanks for all the input!


The Apisto is sold as a Viejita "red neck", don't laugh :) I've been corrected on the Apisto Forums (yes there is a forum for everything under the sun) that it is a Apisto Macmasteri - At least that's what they call in in Europe. I purchased it from WetSpot and I would highly recommend them - great service and fantastic fish.

I have it at 8 hours with a 3 hour burst - that sounds like good medium/high light when I check the PAR guide on the forums that Hoppy posted a while back.

I may drop the light an inch and keep vigil for algae...

I thought I could add an extra hour to the quad lamp burst (156W) to make it 4 hours instead of 3. I am cautious that dropping the light an inch increases the PAR for an entire 8 hours instead of doubling the PAR for 1 hour. It seems like a larger swing.

Any ideas? :)
 
#7 ·
What specific light fixture or fixtures are you using. Since my original charts of PAR vs distance were posted here I have seen a lot more data from a lot of different lights, and even more manufacturers are selling T5HO lights. So, I have posted a different set of charts at http://www.plantedtank.net/forums/showthread.php?t=184368 The PAR you get depends on both the reflectors and the ballasts, and different manufacturers use different quality parts of both kinds.

I haven't tried hairgrass yet, at least not long enough to learn much about it. So, I can only go by what is posted here in guessing what it requires.

Since that tank is 18 inches front to back depth a single light fixture with closely spaced bulbs isn't likely to give uniform lighting over the whole substrate. But, if the light is high enough above the tank, it will give relatively uniform lighting. So, I suggest working with only two bulbs, closely spaced, if you have the light high above the tank, but using 2 widely spaced bulbs if the light is right at the top of the tank. But, that changes if you have one of the inefficient T5HO lights.
 
#8 · (Edited)
Hoppy, Thanks for responding :)

I just looked at the new charts and wow, there's a lot more to consider. My unit's not listed there and I'm not sure what the reflectors look like on those units.

I'm using an Aquaticlife 4x36" T5HO unit: http://www.aquaticlife.com/products/286 It has worked reliably and their customer service is pretty good, btw.

You can see the PAR performance in their user manual (Page 4/5): http://www.aquaticlife.com/sites/default/files/specsheets/420036.pdf

I've got 2 of the original Aquaticlife 6000K bulbs (8 months old) and 2 Zoo Med Ultra Sun Trichromatic Super Daylight Bulbs 6500K (http://www.amazon.com/gp/product/B003HD29EW/ref=wms_ohs_product). (7 months old)

The reflectors are 1/2 parabolic but each bulb has a reflector.

The unit is 9" across, the bulbs are evenly spaced and 8" apart.

I'm starting to think to try this:
  1. Add another hour of burst for 4 hours of 156W, wait a week.
  2. If that doesn't work go back to 3 hours burst, and drop the light 1" and wait a week.
  3. If that doesn't work, add another hour of burst, and wait a week.
 

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#9 ·
Thank you for posting that Aquaticlife manual. I added the PAR data to http://www.plantedtank.net/forums/showthread.php?t=184368 along with one of your photos of the reflectors.

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.

I suspect your problem is a CO2 problem. Once you have enough light, and dose fertilizers per an EI method, 90% of the problems you will run into are CO2 problems. I suggest:
1. Make sure you have good water surface ripple over the whole surface. No splashing, but good rippling. This keeps the water oxygenated so the fish can live with high CO2.
2. Make sure you have very good water circulation in the tank, with all leaves on all plants swaying in the current. This gets CO2 rich water to all plants.
3. Increase the CO2 bubble rate just a tiny bit. Watch the fish for distress, and the plants, looking for improvements in their health and growth rate. If the fish aren't distressed, repeat this step about every 3-5 days, until the fish aren't happy - then drop the rate to the last one where they were "happy". Or, repeat until the plants are growing in obvious good health and at a good rate. It may take a week at each bubble rate to do this well.

If you want to do a "noon burst" go ahead, but I think it is better to eliminate that while adjusting the CO2 to an optimum bubble rate.
 
#10 ·
First of all, I really appreciate the input and I'm glad my information
Just to confirm: With two bulbs I'm only giving the substrate ~ 35 micromoles of light, the noon burst is pushing it to ~70 micromoles for 3 hours.

Dropping the light from 33 to 24 inches is a bit drastic, can I do it gradually? I am weary of large changes to CO2 and light - from experience changes to light especially have caused algae outbreaks in the past.

I'm dosing CO2 through an inline diffuser at 2-3bps - for what it's worth, the drop checker is a light green - though I know that's an estimate, etc. I'll increase that by 1bps and wait.

I'll increase the flow - I have a Hydor Koralia pump that runs at night to ripple the surface for flow. I'll adjust the timer so it runs all day.

Could I just gradually increase the light so I have 4 banks on for 8 hours and keep the 70 micromoles at the substrate?
 
#12 ·
I am not a particularly active member on this forum mainly because I am English & post on the English forums but 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 ...
We believe you don't need to use high light because you are enriching your tank with CO2 and in fact, as we try to point out repeatedly, enriching with CO2 actually allows you to use LESS light, the more C02 the less light required & therefor less algae That's how amazing CO2 is!
Here is a nice long read .... http://www.tropica.com/en/tropica-abc/basic-knowledge/co2-and-light.aspx
 
#16 ·
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.

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?
 
#13 ·
Very true but I didn't change the fertilizing or the CO2 and with a longer lighting period my plants perked up. Not talking about a minor change. The Kawagoeanum went from 3" leaves and 6" of healthy stem to 4" leaves with 18" of healthy stem. The hairgrass stand thickened within 2 weeks and was 6" tall when I pulled it out. My hairgrass grows tall when light is low, I still had quite low light. There is a minimum length of day for a given system and I was below that point.
 
#14 ·
70 micromols of PAR isn't extremely high light, so you can use that continuously if you want to treat the tank as a high light tank. That means you absolutely need to keep the water well oxygenated so you can jack up the CO2 concentration to match the plants carbon demands at the fast growth rate that high light causes. To get that CO2 to the substrate level for the hair grass you also have to make sure the grass is waving in the current, demonstrating that it gets "fresh" water continuously. And, you have to be very conscientious about doing tank and filter maintenance, to avoid causing algae with the buildup of organic debris. Then you need to adjust the CO2 bubble rate upwards just a little bit, every few days, while keeping watch on your fish, and observing the plants to see what effect the increases are having. Do this until you get good growth, and until the last increase didn't improve the growth. Finally, if you do start getting BBA, remove it, kill it, immediately or you will soon have a black carpet. If you enjoy all of that work, you will also enjoy the rewards of having a good high light tank.
 
#20 · (Edited)
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?
 
#21 ·
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.
 
#22 ·
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.
 
#25 · (Edited)
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/showthread.php?t=127131
 
#27 · (Edited)
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?
 
#26 ·
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.
 
#31 ·
Update: I lowered the lights to 30"-31" from the substrate last week. No algae issues. The increase CO2 has been making the plants grow a bit faster, I've been pruning. The hair grass is growing but not much thicker than the week before.

I just dropped it to 28"-29" from the substrate - I'm going to do a gradual 2-3" a week and watch. I've dropped the 4 bulb burst to 2 hours and 2 bulbs are on for 6 hours for a total of 8 hours photoperiod. Next week, I'll drop the light to 26" from the substrate and drop the 4 bulb burst to 1 hour so I don't over do the light.
 
#35 · (Edited)
It's been 9 days and I'm holding at 28" from substrate.
I've gone down to 1 hour of burst 4x39W and 7 hours of 2x39W. I am at 4bps CO2 - I need to clean my inline diffuser before I drop the lights further - It's producing occasional bubbles and it's been 8 months since I cleaned it. Once that happens, I'll get better CO2 diffusion and I'll feel comfortable dropping the lights more.

Currently I've noticed a fine mist of hair algae on the glass after a week. I normally have very little visible algae on the glass after a week. I'm weary of dropping the light further for fear of a algae bloom. I trimmed the hair grass, which seemed to be growing thicker. I'm going to wait a week to see if it's any thicker coming back.

If the grass is growing thicker (albeit slowly), I may not need to drop the light further. If not I'll drop the light another 3" (to 25" from the substrate) remove the burst and keep it at 8 hours 2x39W and adjust the CO2 accordingly.

EDIT: When I trimmed the hair grass there is residual algae at the base (It's been there since the very first algae bloom) - I have a feeling that it may be the keeping the hair grass from growing thick...
 
#36 ·
I Suggest Adding A UV Sterilizer to Your Aquarium And Moving Your Light Closer

The hairgrass is alive, but quite thin compared to when the light was closer (When I set up the tank).
I do not want to have an algae outbreak again so I'm toying with dropping the light an inch to increase the PAR value at the substrate surface, alternatively, I can increase the photo period or the amount of light

I've read that dwarf hairgrass likes 2WPG or more. That being said, I know to focus on PAR vs WPG as a measure of effective light.




In my experience, Dwarf Hairgrass can survive in a lower light condition, however, does much better with higher lighting, CO2, fertilizer tabs and liquid fertilizer dosing at least once a week.

I have noticed that a number of people follow the EI dosing index which seems to work well for them. However, this can become very expensive over time.

I maintain a few planted aquariums with both dh and microsword and have found that it is nearly impossible to create the perfect chemical balance to achieve equilibrium in an aquarium. There are simply too many variables which affect the water column.

I have, however, found that using uv sterilization in my aquariums has not only ridded my tanks of green or cloudy water, but also allowed my plants to propagate more successfully, simply because there are less organisms in the water column which were feeding on the nutrients that my plants also required. This means that my plants no longer have to compete with these organisms as they did prior to the addition of the uv sterilizers.

Not only are my plants healthier than before, my fish are also much more active, and their colors are more vivid due to the better water quality.

I have been using uv sterilizers for the past year and half and cannot over emphasize their importance in helping to maintain a healthy water column.


As for lighting, I use Hagen GLO light fixtures with 6700 Kelvin bulbs in some tanks and a combination of 6700K and 18000K in others, and they work quite well.

I am presently setting up a 5.5 gallon nano aquarium to house some shrimp in, and looking for a good nano light. The Fluval CP mini is about 12 or 13 watts, which might work well, since I want to keep dh and microsword in this tank as well.

However, I am also considering the AquaTop Nano Type P for this aquarium. Yet, at only 7.5 watts, or about 1.3 watts per gallon in my 5.5 aquarium, I am not sure if this light will be powerful enough to grow these plants successfully, even if its 6500K spectrum is ideal for them.

I have been unable to find any independent reviews on the AquaTop Nano P light, so I may just have to purchase one to determine how well it works.

It's a very high tech and sleekly designed lighting system which usually sells for about $70 - two and a half times what the Fluval mini sells for.

And if I were to purchase two mini's that would equate to about 26 watts of light - roughly three times the power of the AquaTop.

Given this, at least on the surface, the AquaTop seems overpriced. However, when you consider the cost of some of the ADA lighting fixtures (and their low watts per gallon) the AquaTop may turn out to be good value if the light is capable of supporting plants like dh and microsword.

As for the importance of PAR over watts per gallon, Takashi Amano's planted tanks grow quite well under very low lighting conditions, so perhaps the AquaTop Type P will work fine.

I may try it and will update this post based on my experiences with the AquaTop light.
 
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