Algae control

[Mebbid]

So a common algae control tactic has always been to reduce the photo period of a tank and it obviously works very well. But due to my overly curious nature I feel the need to ask why exactly does this work?

 

[BBradbury]

Hello Mebb...

Aquautic plants need water, nutrients and light. If you limit or take away one, then the growing process (photosynthesis) can't take place.

B

 

[Mebbid]

Hello Mebb...

Aquautic plants need water, nutrients and light. If you limit or take away one, then the growing process (photosynthesis) can't take place.

B

Yeah, I got that already but why does limiting light to a shorter amount of time affect algae. Bringing the photo period from 10 hours down to 6 should drop the algae growth down by 40% but instead it appears to not even grow.

Then there is the suggestion for a siesta period that I've seen thrown out there a dozen times or so.

 

[Billbug68]

Yeah, I got that already but why does limiting light to a shorter amount of time affect algae. Bringing the photo period from 10 hours down to 6 should drop the algae growth down by 40% but instead it appears to not even grow.

Then there is the suggestion for a siesta period that I've seen thrown out there a dozen times or so.

From what I've read and understand, algae typically takes longer to start the photosynthesis process than plants, which is why shorter photoperiods help control algae, but still allows plants to grow.

 

[BBradbury]

Hello again Meb...

Okay. If we need to dig further, I believe the growth is dependent on the number of micromoles a plant gets. Apparently, moles is a measurement of light that penetrates the water. The deeper the water, the fewer micromoles. Most aquatic plants, including algae require a minimum of 30 micromoles. Fewer than this and the plant will grow very slowly or stop altogether.

My explanation may be a bit off, but those are the facts as I understand them.

B

 

[Billbug68]

Lets say for example... You're dosing pps-pro, which is theoretically dosing only what your plants need in a given day. Well, if you leave the lights on long enough for the majority of nutrients to be exhausted, photosynthesis slows down or seizes in the plants. Algae needs far less to grow than aquatic plants, so the algae takes over once the plants growth slows. That's why you see a lot of algae blooms, say when you go on vacation and don't dose ferts for a few days or a week. You bottom out on... Lets say, nitrate, a macro nutrient key to your plants growth, then the algae takes advantage of this situation and grows on far less nutrients then your plants. I've personally experience this when leaving for a few days, or just being plain lazy and not dosing my ferts. Forget to dose for a few days, and boom! There's that dreaded BBA again! It's all one big balancing act!

 

[Mebbid]

From what I've read and understand, algae typically takes longer to start the photosynthesis process than plants, which is why shorter photoperiods help control algae, but still allows plants to grow.

This is what originally prompted my question. Reducing the photo period down to 6 hours daily shows suppressed algae growth. The nutrients are in the water and being used by the plants but if the algae worked in a similar fashion to plants then it would still be growing out of control because of the free nutrients that hadn't been absorbed by the plants yet.

I have a hectic schedule and have been told more than a few times that I should adjust it down to at most 8 hours daily. But my lighting schedule is set to a 6 hour on / off cycle What difference does it make running my lighting like that as opposed to 8 hours on and 16 off.

 

[Billbug68]

This is what originally prompted my question. Reducing the photo period down to 6 hours daily shows suppressed algae growth. The nutrients are in the water and being used by the plants but if the algae worked in a similar fashion to plants then it would still be growing out of control because of the free nutrients that hadn't been absorbed by the plants yet.

I have a hectic schedule and have been told more than a few times that I should adjust it down to at most 8 hours daily. But my lighting schedule is set to a 6 hour on / off cycle What difference does it make running my lighting like that as opposed to 8 hours on and 16 off.

I'm not sure if anyone can truly explain exactly why... There are some algae that thrives in the same conditions as plants, and some that thrives in other conditions... It's just commonly accepted that there is a balancing act, and if you provide the right conditions for your plants to thrive, algae should be minimal... You just kind of have to accept that... If we had all the answers and every tank was the same, the hobby would be too easy and no fun!!! Haha if you're doing a split photoperiod, I'd try on for 4 hours, off for a couple, then back on for 4. 12 hours total seems to be too much, and if you're still seeing problems, it's probably one of the factors.

 

[Mebbid]

O do the same photoperiod on 2 different tanks with completely opposite results.. my 55g is doing amazingly well while my 10g has been trouble since it started.

 

[Billbug68]

O do the same photoperiod on 2 different tanks with completely opposite results.. my 55g is doing amazingly well while my 10g has been trouble since it started.

Exactly. No two tanks are the same, you have to find what works for each individual setup.

 

[aqua_chem]

I think the one thing we know for sure is that it's complicated. I've heard a few theories, ranging from reasonable to deranged. Probably the most reasonable theory is not so much that algae takes longer to start photosynthesis (which seems the opposite of what is probably happening), but rather that plants get a much stronger start to photosynthesis and slowly taper out over the course of several hours such that near the end, algae is disproportionately more active. Plants need a dark period to process their synthesized products, effectively clearing their loading bay for a new batch of sugars. Algae, on the other hand, is a much simpler organism and therefore probably is not as limited by the light/dark cycle necessities.

 

[Billbug68]

I think the one thing we know for sure is that it's complicated. I've heard a few theories, ranging from reasonable to deranged. Probably the most reasonable theory is not so much that algae takes longer to start photosynthesis (which seems the opposite of what is probably happening).

I really shouldn't have put it like that, I've read it several times, but do not necessarily believe it to be true... I think my second response is closer to how you explained it...