# Light too strong?



## Staffylover (18 May 2016)

I have an 18w Aqua one sunlight tube on a 35l tank and I'm wondering if it could be too bright?  The light is on approx 5-6 hours per day 

How do you work out the correct lighting for a tank? I bought this tank second hand and the light unit is not the standard one that comes with the tank, the standard light is an 11w tube

Thanks


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## rebel (18 May 2016)

It depends in your co2 levels. Ultimately you will know depend on plant growth. Or with a par meter.


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## Dr Mike Oxgreen (19 May 2016)

18W of fluorescent light over a 35 litre tank is 2W per US gallon. That is a perfectly acceptable, fairly high level of light.

But light needs to be balanced by CO₂ and fertilisation. A lot of light without sufficient CO₂ and fertilisation to support plant growth will result in algae problems.

With 2W per US gallon, you'll definitely need a moderately generous fertilisation regime, together with some form of CO₂ supplementation either by pressurised CO₂ or by a liquid carbon supplement.


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## dw1305 (19 May 2016)

Hi all, 





Staffylover said:


> I have an 18w Aqua one sunlight tube on a 35l tank and I'm wondering if it could be too bright? The light is on approx 5-6 hours per day


I don't worry about light intensity, I just have a high plant density  when I have a light that produces more PAR. 

I have a floating plants in the tanks, because they aren't CO2 limited, and you can use their <"health and leaf colour"> as a proxy for when to add fertiliser. 

Brighter light = a higher coverage of floaters.

cheers Darrel


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## micheljq (19 May 2016)

Floaters are not always the perfect solution, the problem being they can cut the light for the other plants below.

Michel.


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## Staffylover (19 May 2016)

I do have some floating plants that I added last night, they cover about a third of the waterline. The last ones I had started to turn yellow so I removed them.

In terms of ferts I have profito fertiliser and flourish excel, which would be the best one to use?


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## dw1305 (20 May 2016)

Hi all,


micheljq said:


> Floaters are not always the perfect solution, the problem being they can cut the light for the other plants below.


That is the idea really, they aren't CO2 limited, so you can use them to reduce light intensity to the submerged plants.

You have to have a balance between light intercepted and light transmitted (which probably only comes with experience for any particular aquarium/light/filter combination). Have a look at <"Windowsill Nature">.


Staffylover said:


> I do have some floating plants....... The last ones I had started to turn yellow so I removed them.


Now that is really useful, because it tells you straight away you are deficient in at least one nutrient.

It has to be nutrients because:

your floating plants have access to 400ppm CO2
and they are receiving plenty of light (PAR).
If nutrients weren't limiting then the plants would be "leaf" green, even in high light intensity. This is some growing, as an invasive alien, in a Californian irrigation channel where I would guess it is receiving a lot nutrients as well as a lot of light.

View attachment 99928

I've had some Frogbit in high light (they are in the glasshouse) with moderate nutrients and very active aeration, they grew very well for a while, but are now showing signs of iron deficiency. I'm pretty sure it is iron deficiency, because it is effecting the new leaf, and iron deficiency both causes chlorosis and is immobile within the plant (it can't be moved from older to younger leaves).

I've never had this happen before, using this growing system (they are for some experimental work) but I've never had such vigorous aeration before, and I assume the difference is that all the iron has oxidised.

It is the top plant in the image below.

View attachment 85536

The bottom plant is one that has been grown in high light (it is on a S. facing windowsill), but has been nutrient deprived.

You can't see quite so well, but it is the older leaves that are yellow. The nutrient deficiency that has caused yellowing is almost certainly either nitrogen (N) or potassium (K), both of which are required in large amounts by the plant, and are mobile within it, allowing the plant to export these nutrients from the older leaves to the newer leaves.

If I added the appropriate nutrient, then I would see a different response. In the case of the mobile elements (bottom plant) I would get a pretty instant greening.

In the top plant the old leaves would remain chlorotic, but the new leaves would be green.

cheers Darrel


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## zozo (21 May 2016)

dw1305 said:


> You have to have a balance between light intercepted and light transmitted (which probably only comes with experience for any particular aquarium/light/filter combination). Have a look at <"Windowsill Nature">.



Thanks for that one Darrel, intresting read, i'm kinda in the same boat as this setup, should have found it sooner.. My new open top low tech is directly under a roof window and now since the sunny cloudless days are arriving i'm amazed how much light this throws into the tank. Had to massively cut back on the artificial light (near BBA explosion). And also how the tank reacts to it is intresting, having Hygroryza aristata as floater since a few months, first it exploded as crazy and now is showing deficiencies.. Kinda looks like a nitrogene deficiency, since i'm using tropica complete it's an educated guess, still in the process of finding out how much extra to add.. The salvinia still feels ok, but hygroriza definitely in trouble.


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## dw1305 (21 May 2016)

Hi all,





zozo said:


> Hygroryza aristata as floater since a few months, first it exploded as crazy and now is showing deficiencies.


That is better than I managed with it, I think it likes harder water and a lot more nutrients than I supplied it with.

Cheers Darrel


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## zozo (22 May 2016)

dw1305 said:


> Hi all,That is better than I managed with it, I think it likes harder water and a lot more nutrients than I supplied it with.
> 
> Cheers Darrel


I got relative soft water, got about 5 small cuttings and it exploded straight away like crazy stayed lush and green till it covered 2/3 of the tank with in a month or so. Then the deficience started to show, it's like it's excausting the tankwater..


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## dw1305 (22 May 2016)

Hi all, 





zozo said:


> I got relative soft water, got about 5 small cuttings and it exploded straight away like crazy stayed lush and green till it covered 2/3 of the tank with in a month or so.


I might have another go with it then.

My suspicion would be either a lack of nitrogen (N) or potassium (K), possibly the latter.

cheers Darrel


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## zozo (22 May 2016)

dw1305 said:


> Hi all, I might have another go with it then.
> 
> My suspicion would be either a lack of nitrogen (N) or potassium (K), possibly the latter.
> 
> cheers Darrel


That's my trouble at the time, using profito for the micro's amd tropica complete for the npk part, so i never know which insufficiency it realy is in this case.. It's time to get my some dry ferts to mix my own..


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## zozo (7 Sep 2016)

dw1305 said:


> I <"struggled with"> _Hygroryza aristata_



You might find intrestening to know i switched in fert regime and bought me some KH2PO4 and started dosing this.. Did it for a strugling java actualy and noticed the H. aristata reacting to it much sooner and sudenly doing realy good, no more browning of it's leaves, getting a bright shiny color and even erecting it's new young leaves almost verticaly above the surface, something i've yet not see it do before. I started out with quite a lot and grew explosively and then suddenly started to die off as fast as it grew.. 

I'm not 100% sure but it suspect since the java was in trouble as well and loves potassium, that it's the aristata taking a lot of potassium from the watercolumn. This or the phosphate but KH2PO4 did the trick on it..  And the little i have left now is realy flourishing..

Here a pic of the little one erecting since it gets thsi stuff..


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## Timon Vogelaar (7 Sep 2016)

That's nice Zozo! I have all ferts as wel because i wanted to dose EI. 
Later on i figured i had better results with dosing profito. And now i'm dosing NPK as wel. 

However, this is not the first time i read on Ukaps that members having good experience dosing extra Potassium. 
I don't really like dosing PO4 and NO3 because i think there is enough available in my almost 5 weeks old setup. 
I have KH2PO4 but i don't know a recipe to dose it. How many should i dose?


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## zozo (7 Sep 2016)

Timon Vogelaar said:


> That's nice Zozo! I have all ferts as wel because i wanted to dose EI.
> Later on i figured i had better results with dosing profito. And now i'm dosing NPK as wel.
> 
> However, this is not the first time i read on Ukaps that members having good experience dosing extra Potassium.
> ...


put 3.6 grams (4 gram may also) in a 500ml bottle, top it off with demineralized water and shake it..

2ml from that solution in 100 litre raises phosphate with 0.1 ppm.. Our aim should be 0.5 to 1.5 ppm phosphate.

It also raises the potassium a little, can't find any description how much potassium it actualy adds. But with this product the aim is rais phosphate. 

if not enough potassium you could use KNO3 (potassium nitrate) to add next to it.
82 grams of KNO3 in 500ml bottle toped off with demi water..

1ml of this on 100 litre will raise potassium with 0.65ppm 
in average 20ppm potassium is held as a good weekly dosage. Harmless if potassium dosage is higher but probably not necessary.

I saw already improvement on this plant with only adding KH2PO4, but also have KNO3 next to it.


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## Timon Vogelaar (7 Sep 2016)

Uhm, i don't understand. Not that your not clear but i have bought my ferts here https://www.aquariumbemesting.nl/nl/onze-producten/poeder-zelf-mengen
It Dutch but to translate this is where i don't understand what you say.

On the K2SO4 bag it says : potassium sulfate is used to raise kalium content 
On the KNO3 bag it says:  potassium nitrate is used to raise nitrate content

You say it is better to use KNO3 to raise Kalium while the company says it's for nitrate...


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## zozo (7 Sep 2016)

Oh sorry i missed some it raises the Nitrate with 1 ppm also.. My aim for now is raising K so didn't notice i forgot to mention the N i only take that as a bonus.
If you read again you see i didn't say anyting about what is beter..  I said what you could use.. 
And also the website you point to gives a discription of how to mix it.. In Dutch, you might want to read that too..


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## dw1305 (7 Sep 2016)

Hi all, 





Timon Vogelaar said:


> On the K2SO4 bag it says : potassium sulfate is used to raise kalium content. On the KNO3 bag it says: potassium nitrate is used to raise nitrate content.
> You say it is better to use KNO3 to raise Kalium while the company says it's for nitrate..


You can have salts that add more than one nutrient. 

When one element is a cation (like K+) and the other an anion (NO3-)  the dissolution of the salt will add both K and N. 

You can work out the % of each element (or compound) added by adding together the RAM of the elements and the RMM of the compound. 

Have a look <"here for the calculation">.

cheers Darrel


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## Timon Vogelaar (7 Sep 2016)

zozo said:


> And also the website you point to gives a discription of how to mix it.. In Dutch, you might want to read that too..



I mostly check up on different sources before i choose what to do  That's why i don't randomly choose to fallow the instructions on there... Thnx for helping out!



dw1305 said:


> You can have salts that add more than one nutrient.
> 
> When one element is a cation (like K+) and the other an anion (NO3-) the dissolution of the salt will add both K and N.
> 
> ...



Thanks Darrel, i'm beginning to understand its not just N,P or K... It works a bit confusing since they this on there box;
NO3 1,00 mg/l
PO4 0,10 mg/l
K 1,30 mg/l
Mg 0,10 mg/l

Makes you think their different components wich they are but added with one or more "powders" like you illustrated.

Is there an salt just for adding potassium?
Wich one can i use best for adding K? Since i have  K2SO4, KNO3, MGSO4 & KH2PO4...


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## zozo (8 Sep 2016)

Nope there isn't a salt like that after all it is salt..  An other option is Seachem Flourish Potassium which is derived from K2O they say.. But rather expensive..

What is best as again a question above my paygrade..  But with adding KNO3 and KH2PO4 should cover the NPK demand pretty close.
And by now i found out adding 1ppm P with KH2PO4 adds 0.4ppm K


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## Timon Vogelaar (12 Sep 2016)

I know this isn't my thread but i am so enthusiastic about the result i get for putting extra K2SO4 in my aquarium.

Recipe;
- Put 45 gram of K2SO4 in 500ml water of tepid temperature. Shake ;]
- For a 50L aquarium 5ml should add 4ppm of potassium.

I did this today before the lights went on and the two hours before the lighting goes out the eleocharis was pearling like madness. It was a bubble bath :]


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