Increase photoperiod by raising light unit?

[Franks]

I've searched for some form of evidence to support this theory but can't find any help.

My tank is doing well and I'm winning a battle against what is now a very small amount of bba. I dose dry fert, Easycarbo, inject Co2 and run 2x24w T5HO 6500K an inch from the 24inch deep tank for 7 hours per day. I'm too worried about increasing photoperiod as is, incase I create an algae bloom again so i thought about raising the light unit a further 4 or 5 inches in order to add another hour of photoperiod.

Does this sound okay? Im concerned about some of my plants such as rotala wallichi and my successfully carpeting Monte Carlo. My other plants I know will be fine.

Any advice or opinions welcome!

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[dw1305]

Hi all,

run 2x24w T5HO 6500K an inch from the 24inch deep tank for 7 hours per day. I'm too worried about increasing photoperiod as is, incase I create an algae bloom again so i thought about raising the light unit a further 4 or 5 inches in order to add another hour of photoperiod.

You can try it, what you need to factor in is that light intensity falls off as <"1/distance for a linear source">.

There is a chart here for PAR, height and light source: <"http://www.plantedtank.net/forums/10-lighting/105774-par-vs-distance-t5-t12-pc-new-chart.html">

cheers Darrel

 

[zozo]

Some Rotala's can be very sensitive to sudden drastic changes to lower light intencity depends a bit on which one, the Indica bonsai doesn't like it and it induces melt, i've killed the Mexicana Goyas completely the only one taking it but growing leggy was the colorata. Monte carlo once fully established and matured doesn't mind and keeps growing well.

Algae is very sensitive, for example i did hang the lights 5 cm back down closer to the tank was enough to get it goin again.. I also experience if you hang that a slow process works best either way, don't do to much at once. It's hard to tell how much without equipment but a few centimeters has a lot of impact.. For me was 15 cm enough to convert a highlight tank with redish rotala MG to a low light tank with no rotala MG at all.

 

[Franks]

Interesting thanks. I've actually set mine 5 inches higher than it was under the same 7 hour photoperiod and everything seems unchanged over the past 4 days except that pearling isn't as drastic with exception to my rotala rotundifolia which is now at various lengths from 5inch to 24inch and growing around 2 inches per day!

My Hottenia palustris may be a good barometer so if this starts to melt, I'll move the light closer.

I'm basically trying to irradiate the remaining tiny amounts of bba which now seem to remain persistent on some of the hardscape.

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[zozo]

I never got 100% rid of it and actualy i don't realy mind, it's only close at the surface mainly the biggest and oldest bucephalandra leaves are affected which i spray with peroxide when emersed during a water change if i see some. Works pretty well i can keep it at bay like that. It comes and goes. Also have it sometimes on the bigger older bolbitis leaves which grows fast enough so i can trim it out. All fast growing plants are not realy growing bba.

Funny is i bought a small java needle leae 6 months ago, which i bought with bba on it.. I t grows relatively well but i never got it clean.. Remarkable java that is, it's almost like it lives in symbiosis with bba, it grows realy fast on this plant.. But must say these plants are all very close to the surface still getting a high lightest intensity.

I'm not so sure if i'm ready to believe that a constant 100% algae free tank excists somewhere. Whatever algae it is.. I rather believe it's a matter of constant maintenance and spot treating proble zones at regular interfals to keep it at bay.

But good luck..