Before I draw reactions let’s go over how PH would swing in a reef aquarium. Autotrophic life during photosynthesis utilizes CO2 ,other marine animals produce CO2 during respiration. The decrease in use of CO2 when lights are off in the main display/refuge allows the PH to drop by increasing the C02 in the tank creating a more acid environment. The unequal balance shifts towards the acid side logically with the lights out due the lack of removal of excess C02 via photosynthesis. Yes pressure, salinity, PO3 will also impact PH but to a lesser degree. So my question is ,why not keep the lights on 24/7 to provide a stable buffer? I’ve read numerous opinions regarding this topic and would like to entertain some more
Well let me see if I can make this sound intelligent and concise:
By leaving the refugium light on 24/7 and the DT light on for 10 hours - when you shut off the DT light you will allow a more acidic condition to occurr for the reasons mentioned above. They would not be as severe and the PH would not drop as significantly as the refugium light it still on.
Now conversly if you leave the refugium light off during the day, and run it on a reverse cycle from the DT lights, the PH decrease you’d experiance from the turning off of the daylights would be nearly negated by the turning on of the refugium light as the macro algaes in the refugium would have been dormant for the prior 10 hours.
[quote=“Cdangel0, post:2, topic:2091”]
Well let me see if I can make this sound intelligent and concise:
By leaving the refugium light on 24/7 and the DT light on for 10 hours - when you shut off the DT light you will allow a more acidic condition to occurr for the reasons mentioned above. They would not be as severe and the PH would not drop as significantly as the refugium light it still on.
Now conversly if you leave the refugium light off during the day, and run it on a reverse cycle from the DT lights, the PH decrease you’d experiance from the turning off of the daylights would be nearly negated by the turning on of the refugium light as the macro algaes in the refugium would have been dormant for the prior 10 hours.[/quote]
so then why not leave the fug lights on 24/7 to compensate for the increase of CO2 in the DT when the lights are off? i know that’s essentially the reverse photo period but i don’t see a reason why not to leave the lights on 24/7? 24 hour vegetative growing will not only buffer the PH,it will also increase the plants photosynthesis and uptake of other molecules such as nitrates and phosphates
because, the co2 level (although higher during the 10 hours the d/t is on compared to just the d/t light alone) will still shift the ph when the display tank lights go off. for simplicity, lets put it into numbers…
if your d/t compensates for 100 parts of co2, and the same from your refugium…
when both are on, a total of 200 parts of co2 are comprimised…ph=8.2. when only one is on… ph=7.8 (or whatever)
but if u only have one on at a time, the ph will buffer at the lower level of co2 in the tank, and the co2 level will not change (much) with the reverse photo
if the ph has buffered at 8.2 with both lights on, then it will still drop when the d/t goes off. by running reverse photo period, they take turns…
wow, i am having an extremely hard time figuring out how to explain this!!! lolol
Trying to find an analogy to better make my point - and understand this is simply my opinion I have no scientific informaiton to back me up - hopefully you can follow me along here
If you are in a room with a 1K candle power lantern and a 50 candle power flashlight. Â if you turn the lantern off you will still be able to see becasue the flashlight is on, it’s just not as effective as your eyes have been accustomed to the lantern light.
Now if you were to stand in the middle of a darkend room for an hour and then turn on just the flashlight the light would appear much brighter as your eyes have been accustomed to the darkness.
I know it’s a stretch but it’s been along day. Â I thiink leaving the fuge light on 24/7 would dilute the benefits you receive from running it on a reverse cycle.
[i]edit: What fishguy said, I like his answer better [/i}
ok…
so theoretically, leaving it on 24/7 WILL give u lower co2 level overall, but it will still fluctuate. and therefore, so will the ph.
[quote=“fishguy9, post:6, topic:2091”]
ok…
so theoretically, leaving it on 24/7 WILL give u lower co2 level overall, but it will still fluctuate. and therefore, so will the ph.[/quote]
but will the fluctuations be enough to seriously impact the organisims in the tank? that’s something i’m currently experimenting with…my hypothesis is it won’t seriously harm my tanks inhabitants…i don’t really see the ph increasing more than .6 with the lights on the refugium being left on for 24 hours
I personally don’t think the PH fluctation is enough with NO fuge light to seriously impact our animals. I think that we are only trying to make it MORE accomodating to our animals by attempting to keep the PH stable.
I’m sure no one is flipping on an small over-head spotlight in the ocean when the sun sets at night.
I know, I know - volume dissipation - it was a joke
check the ph right b4 the d/t lights go off, then check it right b4 they come on… the run the reverse photo and do the same.
hell, im curious now, i think imma try it tonight and tomorrow am. (just gonna be checked 5 hours b4 the lights come back on…)
maybe ill wait til the w/e
lemme know what u come up with
[quote=“fishguy9, post:9, topic:2091”]
check the ph right b4 the d/t lights go off, then check it right b4 they come on… the run the reverse photo and do the same.
hell, im curious now, i think imma try it tonight and tomorrow am. (just gonna be checked 5 hours b4 the lights come back on…)
maybe ill wait til the w/e
lemme know what u come up with[/quote]
i will post my results, but there will be many different variables between our tanks…this should give us some sort of idea though…i’m also going to read up on PH and marine physiology so i can actually deduce what effects different hydrogen ion concentrations impart on varying organisms …gotta love the morris library :GEEK:
dipole dipole! It’s all I remember from chemistry. I think there is some anectdotal benefit to reversing the photoperiod, but I wouldn’t think it is significant overall. Plants use the dark period for opening stomatas and respiration. Is there a benefit for algae to have a rest cycle? Work the same?
[quote=“andrewk529, post:10, topic:2091”]
[quote=“fishguy9, post:9, topic:2091”]
check the ph right b4 the d/t lights go off, then check it right b4 they come on… the run the reverse photo and do the same.
hell, im curious now, i think imma try it tonight and tomorrow am. (just gonna be checked 5 hours b4 the lights come back on…)
maybe ill wait til the w/e
lemme know what u come up with[/quote]
i will post my results, but there will be many different variables between our tanks…this should give us some sort of idea though…i’m also going to read up on PH and marine physiology so i can actually deduce what effects different hydrogen ion concentrations impart on varying organisms …gotta love the morris library :GEEK:[/quote]
variables between the 2 tanks… i planned on checking the ph on my OWN tank both times! (therefore eliminating any variables really) cept maybe .001% salinity from evap, and maybe 1/2 degree in temp!
should i stay up and monitor poop production? just to figure it into the equation?
…sometimes i wonder
[quote=“Jocephus, post:11, topic:2091”]
dipole dipole! It’s all I remember from chemistry. I think there is some anectdotal benefit to reversing the photoperiod, but I wouldn’t think it is significant overall. Plants use the dark period for opening stomatas and respiration. Is there a benefit for algae to have a rest cycle? Work the same?[/quote]
good point, i do remember someone talking about the fuge needing a dark period for one reason or another. dont remember what it was…
in my own experiences, i dont run any light at night, i run my DT lights for 12 hours with a 30 minute dawn dusk setting included, i turn my fuge on when i wake up at 630 and off at midnight, kinda a partial 24/7 but plants of every kind also need to respire at night.
i’ve tested my ph several times at night and the following morning and each test (red sea that comes with the alk) always, always comes out 8.2
just my experience again.
well not all plants require a "rest"period,there’s a few chemical pathways for photosynthesis within plant tissues.
now which pathway does cheato use? i’ll have to do some more searching…as for stomata i’m not sure if i remember correctly, but i think only herbaceous plants are the only species which contain those structures(i’ll have to find my old botany textbook)
as for variables between the two tanks i could type an entire abstract on that issue
[quote=“andrewk529, post:14, topic:2091”]
well not all plants require a "rest"period,there’s a few chemical pathways for photosynthesis within plant tissues.
now which pathway does cheato use? i’ll have to do some more searching…as for stomata i’m not sure if i remember correctly, but i think only herbaceous plants are the only species which contain those structures(i’ll have to find my old botany textbook)
as for variables between the two tanks i could type an entire abstract on that issue[/quote]
Ding…Ding…Ding… We have a winner
Forget about co2 swing when running 24/7 Its not as big of an issue as the cheato will slow its growth reducing its effectiveness to remove Po3 and nitrates
In my new frag tank, i have a small 4 gallon tub of chaeto growing with 36 watt PC light on 24/7. It grows faster than the crab grass in my lawn. in my old frag tank, the chaeto tank light, 3 x 39 watt T5s, is on the same timer as the frag tank. but i also have a 10 gallon prolifera fuge tank in the same system witha 36 watt PC light on 24/7. both chaeto and prolifera grow faster than my tab at a TFP aniversary sale.
when the lights are on, the shrubery consumes CO2 and produces oxygen and carbs. that includes zooxanthalae algae in the corals. the corals consume the zooxanthalae produced O2 and carbs and say thank you very much and generally look happy. the shrubery grows and releases the O2 to the water and with the combo of lower CO2 in the water and Higher ORP, the PH tends to rise with lights on.
when the lights go out, the zooxanthalae, corals and shrubery go to respiration, draw O2 out of the water and exhale CO2 to the water while burning carbs. this push/pull action increases the carbolic acid in the water, which is neutralized by the alkalinity in the water, and with the reduced orp, the PH tends to go down with the reduction in alkalinity…
So why not leave chaeto light on 24/7 and help reduce the swing.
http://www.advancedaquarist.com/2009/6/aafeature
on the other hand, this article/study shows the daily and seasonal swings in temp, and PH on a real reef are far greater than we allow our tanks to swing.
But if you have aggressive cascading bioball type filtration and skimming which aerates the water thereby venting off CO2 and oxygenating the water, the shrubery and corals can be happy too. There will be enough CO2 resident in the water for the plants. it doesn’t all vent away. and nitrates from the bio balls.
Hmmmm???
WHAT? ME WORRY…
OK, might as well read the second part of the article too, on ORP, PAR, UVR and stuff.
http://www.advancedaquarist.com/2009/7/aafeature2
It just gets Curiouser and curiouser.
Ding…Ding…Ding… We have a winner
Forget about co2 swing when running 24/7 Its not as big of an issue as the cheato will slow its growth reducing its effectiveness to remove Po3 and nitrates
[/quote]
i don’t think running the lights 24/7 slows the cheato growth at all… i’ve been in labs where cultures of single cell algea were exposed to 24/7 light constantly…not to mention the greenhouse industries uses of 24 hour photo period. the limiting factor would be the amount of available nutrients not light.
http://www.advancedaquarist.com/2009/6/aafeature
More surprises were noted in the results of the refugium lights-on and lights-off experiments. Upon reflection, the observed results make perfect sense. The process known as ‘reverse daylight photosynthesis’ (or RDP) in theory stabilizes pH (and other parameters such as dissolved oxygen) by ‘balancing’ the effects of photosynthesis and animal/plant respiration. The results noted in this investigation revealed that a refugium illuminated at night does not necessarily negate the effects of respiration of animals in the display aquarium. There are several factors to consider, including refugium size, light intensity in the refugium, respiration rates of the marine algae, fishes and marine invertebrates. Even simple observations of processes involved in ‘balancing’ pH through use of RPD would be time-consuming. At the least, aquarists should be aware that a refugium does not guarantee stability of certain physical and chemical parameters.
great article…
seems to me… there is an awful lot of hub-bub about nothing. our aquariums at their worst dont fluctuate as much as natural reef settings. good to know, and the ph difference is minor and no big deal wether u leave the lights on @ the same time or not.
thanks for the info