Shrimp Tank Questions

[ian]

ps, i'm struggling to find this info, i'll email Tom Barr and see if he can send me it. I remember reading the research, as i say it was on higher light than T12's. There was an actual maximum that plants took in their nutrients and shut up shop as well. It was deffo below 9 hours. This is one of the reasons, we/i would suggest a maximum of a 8 hour photoperiod.

 

[KittyKat]

You don't need 12-14 hours of light to grow HC, that is a fact and given. This doesn't need to be an argument. I'm merely stating that to advise someone to have a photoperiod of this length is ime a silly thing to do, unless they are running really low light. If you can't agree with that then...*shrugs*

It sure did sound like you were arguing! I am not implying that one "needs" anything specific. All I said is that for emersed/shallow water growth, 12-14 hours of light would improve the speed of spreading and rooting. If you like, I will go back and add "in my experience", but it does get rather tiresome, adding that into every sentence

You did come over as making assumptions about what lighting I have experience with and implying that my experience was to be disregarded because of that, so I pointed out that this is not the case. I did not say that one would get less algae with longer lighting periods, I said that it is no guarantee. I am not saying that the two are not related, I am implying that there are other factors to consider and not everyone's experience is the same. I did not even mention anything to do with CO[sub]2[/sub] or fertilisers in my original post: I do not have enough experience with either to go into those.

And can you link me to your evidence ? You can quote me a book i don't have, but i still don't have the knowledge you have at hand.

I will search for relevant and reliable information about photosynthesis of plants in shallow water and emersed, but it will take some days as I am not going to have internet access over the weekend.

For the most part, my suggestion was from my experience with growing the same plant in shallow water, which I tried because of the mention of growing the plant emersed in the book and some propagation guides on plant-related forums suggesting that the plant be propagated in flooded pots. I will be happy to find at least one or two of these if that is what you are asking for. The best evidence I can provide of one woman's experiment working for her is in her book, but as I implied, I do not know if the pre-growing the plant emersed and then filling the tank works or not.

ps, i'm struggling to find this info, i'll email Tom Barr and see if he can send me it. I remember reading the research, as i say it was on higher light than T12's. There was an actual maximum that plants took in their nutrients and shut up shop as well. It was deffo below 9 hours. This is one of the reasons, we/i would suggest a maximum of a 8 hour photoperiod.

I would appreciate it if you could, as I have not read about this part of his work.

 

[ian]

I just read back, and i still can't find an argument here lol.

I have mailed Tom, so i'm sure he'll get back to me soon.

I also stand by my statement regarding the 12-14 hours photoperiod. It's way to long for a planted newb to work by.

 

[ian]

from Clive and Tom Barr (aquatic botanists)

Hi Ian,
One has to be careful to use the proper words so as not to muddy the waters with different principles which, although related, are distinct. Barr noted that submersed macrophyes typically have a photoperiod of about 8-9 hours, after which food production activities decline. These limits don't seem to apply to algae so that long photoperiods tend to encourage algal blooms while having marginal benefits to plants. The expression "maximum uptake" is more accurately associated with the rate of uptake and of food production. The uptake rate will depend on nutrient/CO2 availability during the photoperiod.

The need to optimize CO2 at the beginning of the photoperiod has more to do with the food prodution inefficiencies at lights on due to the thousands of individual photosynthetic reactions. In other words, the engine s just getting warmed up inthe early part of the period. Fixing Carbon is a top priority, so it has to be available otherwise the system is more vulnerable to shortfalls. That's the reason for the 2 hour gas initiation prior to lights on. It's because of our inability to provide good distribution and saturation that we need to do this.

By the 6 hour mark the plants have fixed plenty of carbon and the injection has saturated the water as well as the fact that the system is starting to shut down, so there is much less emphasis on the gas availability by then. That's why we can shut the gas off early without ill effects. A lot of our CO2 problems actually are occurring in the early part of the photoperiod.

Cheers,