24/hour lights, no fish heavy C02 and ferts? Why not!?

[Duskfire Discus]

Quick question, google is pretty daft on the subject:
Would leaving lights on 22-24 hours a day, with high CO2 injection as well as weekly ferts lead to fantastic plant growth or would it just be a waste of Co2 and electricity?
I have a heavily planted high tech 75g, and right now all of that tanks fish are in QT from a skin flukes problem caused by some bad angelfish, (dont buy from petco ever, even if you work there and get a discount :) )
I'm just wondering, while the fish are out, would their be any reason to not do as I suggested? Other then potential algae problems? I have virtually no algae in the tank because I have a fantastic Co2 setup, I don't believe that would change.
People claim plants have a rest cycle, but the rest cycle is caused by the lack of light, they switch gears, stop growing and start producing small amounts of co2, during the day they use up the co2 and the fishies overnight co2 production and grow with the help of the light, so I would reason that as long as co2 is provided as well as nutrients there is no logical reason to have a night cycle, other then to let my lighting units cooldown...

If anyone has any experience or scientific reasons as to why this wouldn't fly, please let me know!

[kwan8911]

I did some research a few weeks ago on planted tank, 24 hours high light might cause algae bloom. Even if it doesn't cause algae problem, people with hight co2 hight light setup often need to trim their plant weekly. So I don't see why you need such long lighting period.


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[pcsb23]

Not scientific but ...

A few years ago I tried a few experiments, not overly controlled but enough to get a feel. One of them involved different photoperiods above "the norm" as it were. I had a relatively small tank of around 120 litres with a 200W HMI over the top and CO2 injection. I had this tank running "normally" with an 8 hour photoperiod and daily ferts using my own version of PMDD. No fish, mix of plants many so called high light type. I was trimming this tank twice a week like this, no algae either. Enriched substrate. Excellent flow & filtration.

Using an accurate nitrate test, not the hobbyist type but the type used in a lab, I tracked the NO3 usage to give me a measure. I could have tracked other ferts but settled on this one. I made the assumption that all ferts would be used in proportion. The aim was to make sure that there was always some NO3 present before re-dosing and to have CO2 stable at around 30ppm.

All experiments were carried out for two weeks, with a week reset period in between where I returned the tank back to where it was.

The first experiment I did was to increase the photoperiod to 12 hours, initial observations were an increase in use of ferts but not proportionally, I'd expected that as I'd increased the photoperiod by 50% to see a similar fert usage increase, it was around 20% iirc. CO2 saturation remained at 30ppm throughout the photoperiod. The tank developed nuisance algae, mainly green spot. No obvious increase in plant growth though logically there had to be some.

The next was to take the photoperiod to 16 hours. Observations were pretty much as above, i.e. marginal initial increase in fert usage and quicker development of algae. By two weeks I had just about lost the battle with the algae on the glass.

The next was to see what would happen with 24 hours, first couple of days as above, but ended up losing plants, crypts went first, cuba followed, utter mess. Aborted after a week or so.

All this taught me was that I may have needed to monitor other ferts, I did increase dosage as the intention is to always have ferts available to the plants, I'm not sure of some went too high or some got exhausted, NO3 didn't so I know that nitrogen wasn't the limiter.

My advice with this sort of thing is it's great fun to mess about, but if the system is working as is leave it alone! If you are getting good growth without issues don't stress the plants and don't upset the balance. If it isn't broke ...

[musicmarn1]

Great info Paul, enjoyed reading that ty :o

[rickztahone]

Plants need a dormant period. Paul's observations are what we would expect in a day to day tank with even high co2 saturation.

[Duskfire Discus]

Thanks all for the responses, decided after reading Paul's comment to leave it alone, very interesting read! Thanks!

[doublediscusjack]

". . . . . all of that tanks fish are in QT from a skin flukes problem caused by some bad angelfish, (dont buy from petco ever, even if you work there and get a discount )."
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If you are raising/breeding Discus, I have a better idea: Don't buy angelfish from ANY source, to put in with your Discus, for angelfish can thrive well with some parasites/pathogens; pass them along to the Discus, that can't tolerate and thrive with them. Additionally, my view is that if you want nice plants, raise plants, but if you want nicest Discus, raise only Discus; no plants. Trying to raise both in same tank EVENTUALLY leads to problems you were not expecting.

[Duskfire Discus]

There are no Discus in that tank, and never had been, Angels and tetras...
But thanks for jumping to conclusions. I do however intend to add in discus as the only fish in the tank once I install a sump as opposed to the hob filters that tank currently has.. CO2 and high lighting doesn't effect discus as much as some people like to think. Especially around here where the tap runs at 8.4 and RO doesn't adjust the PH, too much buffering in the water, CO2 leaves it alone as well.

[plecocicho]

Plants need dark at night for so called dark phase of photosyntesis during wich phosyntetic intermedies done during light phase go to the calvin cycle which in the end produces sugars.during that phasebplants go to cells breathing, so they use oxygen too.