Mystified by no algae presence in highly lit empty aquarium

[John Troy]

I've been dark starting my aquarium for around 4 weeks now, however the last 2 weeks I've been on holiday. I have remote control of the light unit, and just today realised I accidentally had switched the light on a week ago, and its been left on for the past week for 24 hours a day.
Here's what confuses me: I've been getting a family member to add large amounts of fish flakes to help with cycling, and furthermore I'm using RO water which tested around 10ppm for nitrates (my tap water has about 40ppm). Yet there is zero algae?

The only reasons I can think of are
A: my RO water actually has 0ppm nitrates or next to no other micro-nutrients at all and my test kit is inaccurate (but in this case Id expect the breaking down of fish flakes to promote algae growth).
B: my biological filtration has produced de-nitrifying bacteria since im using seachem matrix (but I've heard this is pretty hard to achieve, and isn't actually proven possible in most setups, so I think its unlikely).
C: algae hasn't had enough time to grow (but its been a whole week of 24/7 strong lighting)
However neither of these seem like satisfactory answers, given my water is completely clear with no signs of algae. And I know that there is nothing wrong with my water because biofilm was appearing a few days before. Im completely mystified as to why there hasn't been any algae growth at all.

For reference, im running a 30L nano cube, with an allpondsolutions 1000EF external filter, as of now with zero plants, running a Twinstar 300E light (on about 60% strength).

 

[MrClockOff]

Just wait a little bit longer and you will get the algae. I can see aqua soil which is full of nutrients and also you didn't do any water changes. Adding flakes was unnecessary as all you needed for dark start cycling was in the aqua soil.

 

[John Troy]

tropica aquasoil doesnt release any ammonia, also Its been used before so its fairly depleted. I added the flakes as a precautionary measure.

 

[John Troy]

Just wait a little bit longer and you will get the algae. I can see aqua soil which is full of nutrients and also you didn't do any water changes. Adding flakes was unnecessary as all you needed for dark start cycling was in the aqua soil.

surely in a week given high lighting 24/7 you'd expect algae?

 

[Hanuman]

Not sure what is going on but I do know that the drop checker is upside down...

 

[John Troy]

Not sure what is going on but I do know that the drop checker is upside down...

yeah lol Idk why I did that, it hasnt been in use yet just looked cool

 

[dw1305]

Hi all,

my RO water actually has 0ppm nitrates or next to no other micro-nutrients at all and my test kit is inaccurate (but in this case Id expect the breaking down of fish flakes to promote algae growth).

I'd guess that at least one of the fourteen mineral nutrients required for plant growth is missing. There is a full list in <"What is the “Duckweed Index” all about?">

Plant growth is <"like a car assembly line">, one missing component and you don't get a "car", or in this case any algae.

cheers Darrel

 

[MarcusA]

I think one week is still early enough that it’s not so strange that algae hasn’t shown up. Strange but not incredibly strange.

 

[John Troy]

Hi all,

I'd guess that at least one of the fourteen mineral nutrients required for plant growth is missing. There is a full list in <"What is the “Duckweed Index” all about?">

Plant growth is <"like a car assembly line">, one missing component and you don't get a "car", or in this case any algae.

cheers Darrel

Hi Darrel, thanks for your input, I was thinking that, however im not sure the water in my tank is completely absent of any minerals as last I checked my tds was showing 150ppm (But to be honest I think my TDS metre is pretty inaccurate). Also correct me if Im wrong but isnt it possible for algae to grow in RO water regardless of the lack of minerals, as Its not uncommon for algae to grow in RO storage tanks? Is it that the mineral content is too low to promote fast enough growth that it would appear in a week on high light (basically what you said). Also on a slight tangent, I recently watched a very interesting video suggesting Liebigs law of minimum is very much just a basic approximation, introducing the Redfield Ratio and MLH, but Im just a beginner so not sure what to make of it.

 

[Wookii]

tropica aquasoil doesnt release any ammonia, also Its been used before so its fairly depleted.

When new Tropica aquasoil releases load of ammonia. How long had it been used before? I would expect even rinsed reused soils to release sufficient nutrients into the water column for algae, simply from the fact that sub-layers have been brought to the top during the re-use.

correct me if Im wrong but isnt it possible for algae to grow in RO water

As you are London, I suspect you RO water has more that enough nutrients in also, unless you are running it though some DI resin too.

I suspect you're not seeing algae yet as it simply hasn't been long enough, and your light isn't as bright as you think it is. It's only 1,000 lumens, so at 60% is only 600 lumens. Plenty for plant growth, and maybe too much on a 30 litre cube, but no where near enough for rapid algal growth in a week. Stick it outside in a south facing spot in direct sunlight, and it'd be a different story.

 

[John Troy]

When new Tropica aquasoil releases load of ammonia. How long had it been used before? I would expect even rinsed reused soils to release sufficient nutrients into the water column for algae, simply from the fact that sub-layers have been brought to the top during the re-use.

As you are London, I suspect you RO water has more that enough nutrients in also, unless you are running it though some DI resin too.

I suspect you're not seeing algae yet as it simply hasn't been long enough, and your light isn't as bright as you think it is. It's only 1,000 lumens, so at 60% is only 600 lumens. Plenty for plant growth, and maybe too much on a 30 litre cube, but no where near enough for rapid algal growth in a week. Stick it outside in a south facing spot in direct sunlight, and it'd be a different story.

oh sorry I was wrong about the aquasoil releasing ammonia. Either way I expect its depleted given its been sitting in stagnant water for about 2 years and then dried out. Yeah I dont have any DI so probably so unfortunately. 600 lumens is definitely a lot for a nano cube though right? also isnt it the par thats more important? But thats the most likely reason that it hasnt been long enough.

 

[dw1305]

Hi all

I'm not sure the water in my tank is completely absent of any minerals as last I checked my tds was showing 150ppm (But to be honest I think my TDS metre is pretty inaccurate).

It only needs to be the absence of one nutrient, you can have thirteen of them present in abundance, but if you <"don't have any of the fourteenth?"> You don't get any growth.

Also correct me if Im wrong but isnt it possible for algae to grow in RO water regardless of the lack of minerals, as Its not uncommon for algae to grow in RO storage tanks?

You can have trace amounts of all fourteen nutrients and get growth, but plants can't grow in DI water. In the lab. we used to get green algae in the storage aspirators <"when we used distilled water">, but not in DI water.

Is it that the mineral content is too low to promote fast enough growth that it would appear in a week on high light (basically what you said).

Yes. If you have a complete fertiliser to hand? A small addition should give fairly instant greening.

Also on a slight tangent, I recently watched a very interesting video suggesting Liebigs law of minimum is very much just a basic approximation, introducing the Redfield Ratio and MLH, but Im just a beginner so not sure what to make of it.

The <"Redfield ratio relates to marine phytoplankton">, I'd be wary of putting to much reliance on it.

Cheers Darrel