# I don't understand...



## Tom (10 Sep 2010)

My M. Umbrosum has gone yellow and has brown algae over it just in the last couple of days and the leaves are melting. It hasn't grown since the first trim, however it was growing nicely before I trimmed and switched to TPN+ from TPN.
My rocks are covered in brown and green algae. 
My R. wallichi hasn't so much as grown 1mm in the time I've had it and is now also getting covered in brown algae.

I have been increasing my dosage of both Excel and TPN+ recently, as James' Planted Tank Guide says green dust algae is due to low nutrients and CO2. I have also cut the light from 20w to 9w. I am doing daily 50% water changes after dark so NH3 shouldn't be a problem, and dosing a couple of hours before lights on. Oddly, I had no problems using TPN with no N&P. If the algae is due to not enough nutrients, then I don't understand this. I am currently dosing 5ml TPN+ and 6ml Excel per day. 

Flow should be fine as I have an Ecco 2036 with lily pipes - there are minimal dead spots. Tank is 10 Liter. 

Having said that, my hairgrass is growing great and throwing out new runners 

Any thoughts? I don't understand!!
Tom


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## Tom (10 Sep 2010)




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## Garuf (10 Sep 2010)

Looks alot like diatoms? I wouldn't be overly concerned, just get some ottos? I can't give any incite on the yellow growth, maybe it just need time to readjust to the tanks conditions?


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## ceg4048 (11 Sep 2010)

There is absolutely no benefit in doing a water change in the dark Tom. Why are you doing this? That's an immediate handicap. In your case, the best time to do a water change is just before lights on. You should also dose immediately after the water change, not wait till the next morning. I'm not understanding the rationale being used here. It's almost as if you were assuming this is a non-CO2 tank.

Melting=Poor CO2.

Cheers,


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## Mark Evans (11 Sep 2010)

ceg4048 said:
			
		

> There is absolutely no benefit in doing a water change in the dark Tom. Why are you doing this? That's an immediate handicap.



i've always done that   and dosed straight after. convenience in my case.


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## ceg4048 (11 Sep 2010)

Yeah, but that in gas injected tanks right? No big deal because you can deliver any desired  concentration levels with gas. If you're depending on Excel only then you need every advantage you can get. Dropping the water level purges water from the leaf tissues (dries them) and replaces the displaced water with air which contains CO2. The new water, assuming it's freshly drawn tap, will be high in CO2. If you do this just before the photoperiod then you're giving the plants a boost just when they need it the most. With gas injection the benefit might be negligible, especially if you're a heavy handed injector, but for Excel-only tanks this can be of real benefit, especially if it's a daily water change. All of this is lost at night since CO2 is not relevant in the dark.

Cheers,


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## Mark Evans (11 Sep 2010)

ceg4048 said:
			
		

> Yeah, but that in gas injected tanks right?



yeah, sorry.   

I didn't realise this was a non co2 tank from Tom.

if this is the case, 20w over 10L even with liquid co2, seems an awful lot right?


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## ceg4048 (11 Sep 2010)

Mark Evans said:
			
		

> I didn't realise this was a non co2 tank from Tom.


But you see, that's exactly my point. It isn't really a non-CO2 tank if he's adding CO2 via Excel. What it is though is a low-to-middling CO2 tank, and because of that, the amount of CO2 he can add simply by doing a water change is significant relative to his average daily concentration level. Not only that, but doing this at THE most critical time of the day definitely adds value, whereas this value is sent down the drain if performed at night when the CO2 cannot be used.

Seemingly small changes in routine can send the tank into a tailspin because all these factors are additive. CO2 causes nutrient uptake demand and nutrients cause CO2 uptake demand.

Cheers,


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## Mark Evans (11 Sep 2010)

ceg4048 said:
			
		

> But you see, that's exactly my point. It isn't really a non-CO2 tank if he's adding CO2 via Excel. What it is though is a low-to-middling CO2 tank, and because of that, the amount of CO2 he can add simply by doing a water change is significant relative to his average daily concentration level. Not only that, but doing this at THE most critical time of the day definitely adds value, whereas this value is sent down the drain if performed at night when the CO2 cannot be used.
> 
> Seemingly small changes in routine can send the tank into a tailspin because all these factors are additive. CO2 causes nutrient uptake demand and nutrients cause CO2 uptake demand.



good info mate, thanks


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## Mark Evans (11 Sep 2010)

Clive, for the last hour or so, i've gone over, in my head, the process and I'm pleased to say the pennies just dropped


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## Tom (11 Sep 2010)

Thanks for the explantions Clive - I was doing the water changes at lights out sometimes and before lights on sometimes. I had assumed that as the plants weren't photosynthesizing during the night then the nutrient levels weren't important. If that were true, then I thought the timing of the water change wouldn't matter provided I dosed nutrients each morning. 

I also didn't realize there was so much CO2 in tap water. If anything, I thought there would be less! 

My penny is also starting to drop... albeit in slow motion (Matrix style!)

Cheers,
Tom


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## Ray (11 Sep 2010)

Tom said:
			
		

> I had assumed that as the plants weren't photosynthesizing during the night then the nutrient levels weren't important.


That's a good question - Clive do the plants pump up nutrients during the night? I always assumed that they did & that algae can't?  Of course brown diatoms can grow in the dark so that may be another story...


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## ceg4048 (12 Sep 2010)

Well it's easy to get tunnel vision if we only focus on what's happening in the chloroplast. These are light dependent cells but they are not the only type of cells that the plants have. All the cells respire 24/7 and so there is a lot going on in the plant at night. Cell respiration produces energy from the sugars that the plant built during the day. This energy is used to build some of the products like nucleic acids, amino acids and so forth. The nutrient uptake is a lot less during the dark but does happen and is used in some of these reactions.

But this is a less important issue. During a blackout for example, it's the inability of the algae to produce the carbohydrates that each cell needs for respiration. It's this lack of carbohydrate reserves that dooms the algae during the dark, not whether they can uptake nutrients. Plants have more sugar reserves so a blackout hurts them less than algae, which are lean and which just run out of food and therefore starve to death.

I think that's one of the pennies that needs to drop for a lot of people. 

Light + Water + CO2 = sugar. 

Just take any of those first three out of the equation and no food can be produced. Sugar is produced during the day but not at night. On the other hand sugar is consumed 24/7 so the breadbasket is depleted at night but is filled in the day. If you take the day away for long enough then the breadbasket dries up and the plant starves to death. This happens in algae quicker than in plants simply because their breadbasket is smaller. That's why a blackout works and it's also why some plants are hurt more by a blackout than others.

So think about this equation within the context of what we discussed about the water change CO2 implication and it's clear that I can fill the breadbasket quicker and more reliably in Tom's configuration just prior to the photoperiod, rather than after. Mark never has to worry about this because he is a certified CO2 junkie in need of state sponsored rehabilitation.   His tanks have loads of CO2 available at the right time so this is much less important in his case.

Cheers,


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## Mark Evans (12 Sep 2010)

ceg4048 said:
			
		

> Mark never has to worry about this because he is a certified CO2 junkie in need of state sponsored rehabilitation.



 This is true Clive. I've come fresh out of the 'Clive School Of CO2 Injection' or 'CSOCI' as it's better known.

I always fear a shortfall in co2, not so much the amount, but how _that _amount entering the tank,  is used, through flow and distribution. 

The latest 120cm has it everywhere and can only stay like that with low growing plants...fingers crossed   

god bless inline diffusers


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## PM (13 Sep 2010)

I thought if you were using Excel or full low tech (no co2, no excel), then you are supposed to stop the co2 from fluctuating.

Hence wc's at night. I have just started full low tech and plan wc's every few weeks (when i need to clean) at night.


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## ceg4048 (13 Sep 2010)

Hi,
    It's a really important point to realize that using Excel counts as high tech, not low tech. The technology that is "high" or "low" has nothing to do with using regulators or high lights. "High" technology has strictly to do with the fact that we are enriching CO2. "Low" tech has to do with the fact that CO2 is NOT being enriched.

The difference between gas injection and liquid carbon is strictly a matter of degree.

Cheers,


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