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Blackout After Dosing Ferts?

676 Views 3 Replies 3 Participants Last post by  AquaAurora
Does anyone do a blackout 1 day a week? I ask this because I have my tank very balanced and dialed in, for example I have to dose nitrogen weekly because my tank sits at plant load is heavier than my bio-load. Usually the day after I dose ferts the nitrates are at a maximum of about 3ppm and by the following day they are back to 0ppm. So my plants get fertilized every week but are without (at least nitrogen) for several days at the end of every week.

My thought was not having the lights on the day after you dose fertilizers so that the algae does not grab the nutrients when they are at their highest concentrations. My particular tank would probably not benefit much from this being so balanced but maybe someone elses could? I know if I go through the work to clean my tank and make it look perfectly clean I will do a blackout until I am ready to take a picture of it, buying as much time as I can allowing the water to be polished.
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I have been wondering this myself so I hope someone answers you. I dose EI ferts once a week (third the recommendation because I have low light/no C02). I add root tabs once a month for some of the plants that seem to need it- particularly my biggest crypts and aponogetons.My tank is getting to be more stable, but I've noticed that the day after I do root tabs I always have higher nitrates and an outbreak of fine thread algae almost like sparse pale fur on some leaf surfaces. Even if I dose less on the dry ferts the day of doing root tabs, I get this.

I think next month I will try a blackout day and see if it helps.
I also wonder, if the blackout will lock up the plants ability to process the dosed ferts. They may need light to process them?
I also wonder, if the blackout will lock up the plants ability to process the dosed ferts. They may need light to process them?
Correct they will not absorb and use ferts if there is insufficient light for photosynthesis. Just as plants don't absorb nitrogen (nitrates) when lights are off.
The only time I do blackouts is if I [censor] up and leave the light timer to 'on' instead of 'timer mode' and go over 12 hours of it 'on' (usually tank lights are on 7 hours) because I forgot to switch it back-typically happens when doing a water change-need to see so i don't suck in a fish so turn timer light to 'on' state. Not too often though. In these instances i don't dose new ferts until the blackout time is over.
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